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Last update of this page: September 30, 2014, 11:26 am ET
This page provides all the information you need regarding the mini-laboratory used for experiments on SSEP Mission 6 to ISS — the NanoRacks Fluids Mixing Enclosure (FME) Mark II, which NanoRacks has also dubbed a “Mixture Tube”. Here you will find all the specifications for the mini-lab, a description of its straightforward operation, and all the constraints on your experimental design, including constraints due to the time it takes from submission of your experiment, to arrival and operation on ISS, to return to Earth.
Before reading this page, be sure to read the Designing the Flight Experiment page. It will help you understand how to start thinking about a possible experiment.
1. Introduction to the FME Mini-Lab
The FME is a very simple mini-laboratory designed to carry small samples of fluids and solids—the Experiment Samples—and provides for the samples to be mixed at an appropriate time in orbit. This allows you to explore the effects of microgravity on a physical, chemical, or biological system contained in the mini-lab.
The FME consists of a single silicone tube that can contain one, two, or three separate volumes of fluids and/or solids. The tube is divided into sub-volumes using up to two tube clamps. You can think of the FME as one, two, or three small test tubes that can be mixed in orbit.
Each tube is 6.7 inches long (170 mm), with an outer diameter of 0.5 inches (13 mm) and an inner diameter of 3/8-inches (9.5 mm).
Each flight experiment for SSEP Mission 6 to ISS must be designed for operation in a FME. The SSEP payload to the International Space Station will contain one FME for each flight experiment. The FMEs will be placed in a Payload Box which can contain up to 12 FMEs. SSEP flight experiments will share the Payload Box with flight experiments from professional researchers in academia, industry, and government. NanoRacks has the ability to fly multiple Payload Boxes to accommodate a payload of more than 12 FMEs. Once in orbit, the Payload Box is placed in a rack on Kibo—the Japanese Experiment module (JEM) on ISS.
2. Operating the FME Mini-Lab
The FME is a single silicone tube that can be divided into sub-volumes via clamps. At a prescribed time, an astronaut can release a clamp allowing the contents of the adjacent volumes to mix. Once a clamp is released, shaking the FME is strongly recommended to ensure mixing. Shaking the FME is a “Special Handling Request” that the student research team can request.
There are three types of FMEs depending on how many different ‘test tubes’ your experiment will need—
Type 1 FME: contains only 1 experiment sample and no clamps. An experiment using a Type 1 FME by definition requires no mixing. Figure 1 provides a graphic of a Type 1 FME. Download Figure 1 as a pdf
Type 2 FME: contains 2 experiment samples, with the samples divided by 1 clamp. The samples do not need to be equal in volume. Figure 2 provides a graphic of a Type 2 FME. Download Figure 2 as a pdf
Type 3 FME: contains 3 experiment samples, with the samples divided by 2 clamps. The samples do not need to be equal in volume. Figure 3 provides a graphic of a Type 3 FME. Download Figure 3 as a pdf
- Air Voids: A volume containing a fluid does not need to be completely filled. Air voids are fine.
- Sterilization: If heat sterilizing an FME, do not exceed 390 deg F for the silicone tube, or 200 deg F for clamps and end caps. Heat sterilization is not recommended for tubes partially filled with samples given it may damage those samples, or cause expansion of samples already loaded and possibly lead to failure of the tube or clamp. Alternatively, sterilization can be done by gas (e.g. ETO), radiation, or chemicals.
3. Fluids Mixing Enclosure (FME) Kits – You Get the Real Flight Hardware and Load It for Flight to ISS
As part of the Baseline Program Cost, each participating community will receive a package of five Fluids Mixing Enclosure (FME) Kits, each Kit providing all the parts for the assembly and loading of a flight certified Type 1, Type 2, or Type 3 FME.
Each FME Kit provides the ACTUAL flight hardware. Each experiment selected for flight will be conducted in an FME that the student team assembles from one of their Kits, loads, seals, and ships or hand-carries to NanoRacks in Houston for flight on the ISS. When NanoRacks receives your FME, they will heat seal two polyethylene bags around it to serve as a second and third level of containment (see Section 6.1 below), load it in the Payload Box, and deliver the entire payload to NASA for integration into the launch vehicle.
On return to Earth, the sealed FME will be shipped back to you, or provided to your team’s representative in Houston. Once received, the student team conducts their own harvesting of the samples from the FME and analysis of the samples.
This approach allows students to get broad experience in all aspects of their experiment design and operation, and there is no third-party handling of the experiment samples before they are sealed in the FME destined for space. The other four FME Kits can be used by your community to demonstrate and assess the operation of the FME mini-lab, design and refine experiments, and conduct formal ground truth experiments (see Section 5 below) while the flight experiment is ongoing. The FME Kit is therefore also an exceptional experiment design tool, providing an understanding of precisely how the experiment can be conducted on ISS.
While experiments that are being proposed as part of the community-wide design competition most likely can be tested using standard laboratory test tubes and mixing protocols, the selected flight experiment should likely be assessed and refined using an actual FME, before the flight FME is loaded and shipped to Houston. If a participating community would like more than 5 FME Kits, they are available as packages of five Kits for an additional cost.
Important note: NanoRacks has created a PDF titled “FME Mark II Assembly and Loading”, and a video, with detailed instructions for assembling, loading, and sealing the FME. These documents are available for download from the Document Library.
4. Mixing the Experiment Samples in the FME Once in Orbit, and Astronaut Handling
Each FME is self-contained, allowing each student flight experiment team to define when mixing is to take place for their experiment, which can require up to two interventions by an astronaut in the case of a Type 3 FME. To mix samples in the FME, the astronaut is instructed to unlatch the appropriate clamp, and should also be instructed to shake the tube. It is also possible to define other actions by the astronaut assigned to the SSEP payload besides unlatching clamps. For example, you can request the FME just be shaken at appropriate times. Note, however, that to ensure consistency with crew schedules, NanoRacks in concert with NASA has defined five specific days for crew interactions with the FMEs while the SSEP payload is aboard the space station. Each student flight experiment team can only choose days from the Table below for the assigned astronaut to manipulate their FME, days which best fit their experiment design.
Scheduled Crew Interaction Days for Mission 6 to ISS
For the dates listed below, A=0 is the Time of Arrival, when the SSEP experiments payload is brought from the ferry vehicle through the hatch on ISS, and D=0 is the Time of Departure, when the payload is moved through the hatch on ISS and loaded onto the ferry vehicle for return to Earth.
|1||on arrival at ISS||A=0|
|2||during first week||A+2|
|3||2 weeks prior to departure||D-14|
|4||in week prior to departure||D-5|
|5||in week prior to departure||D-2|
Important note on adjustments to scheduled crew interaction days: ISS astronauts do not have tasks scheduled on weekends. The above schedule may require adjustment if any of the interaction days above fall on a weekend.
Important note on the duration of your experiment: the significant length of time from handover of your FME to NanoRacks in Houston through its arrival on ISS implies that most experiments will need to be in a dormant (inactive) state until arrival on ISS (see Section 6.3 below for constraints imposed by the timeline). If your experiment is inactive until initiated with a mix, then your experiment can be initiated (activated) on any Crew Interaction Day listed above with an astronaut unlatching a clamp. In addition, your might design an experiment that can also be terminated with a second mix, which is possible using a Type 3 FME. You then have the latitude to define how long your experiment should proceed in microgravity before de-orbiting and returning to Earth. But only the Crew Interaction Days in the Table above are allowed. For example, if you only want your experiment to run for two days on ISS, you can choose Crew Interaction Days that are two days apart (A=0 and A+2 above). If you want your experiment to run roughly two weeks, choose Crew Interaction Days that give you a roughly two-week run time for your experiment (D-14 and D-2 above). Also note that the crew interactions you define for your experiment are independent of any other FME experiment being performed.
For the five Crew Interaction Days in the Table above, an experiment can run for: 2 days, 3 days, 9 days, 12 days, and if the time from Arrival to Departure is 4-6 weeks, an experiment can also run for the entire time it is aboard ISS, as well as 1 to 2 weeks short of that entire time.
Important note on the order of unlatching the two clamps for a Type 3 FME: to guard against human error in unlatching clamps for the Type 3 FME, Clamp A (located between Volumes 1 and 2) will be the first clamp unlatched by the astronaut, and will be color-coded as a GREEN clamp for the astronaut.
There are two possible configurations for unlatching Clamp B (located between Volumes 2 and 3):
i) Clamp B is unlatched at the same time as Clamp A. In this case Clamp B will also be color-coded as a GREEN clamp.
ii) Clamp B is unlatched on some later Crew Interaction Day. In this case, Clamp B will be color-coded as a BLUE clamp.
5. Ways to Think About Using the Different Types of FMEs—Some Examples
There are countless experiments that can be done in the FME mini-lab. To gain an understanding of the kinds of experiments possible in microgravity, first read the Designing the Flight Experiment page, and then the Microgravity Science Background and Microgravity Experiment Case Studies documents available for download at the Document Library. Here are a few practical applications of the FME mini-lab to microgravity experiments—
A Type 2 FME: provides an excellent protocol for a significant class of biological experiments. A dormant organism (e.g., freeze-dried bacteria or cells) could be placed in one volume. A suitable growth medium could be placed in the remaining volume. Once in orbit on ISS, the clamp between the two volumes is unlatched and the experiment is initiated. As one example, the Type 2 FME is perfectly suited for an experiment exploring how a seed will germinate in microgravity. The dry seed or seeds can be placed in one volume of the tube, and in cotton to wick the growth medium when the clamp is unlatched.
A Type 3 FME: is suitable for any experiment that requires three separate samples to be brought together. A good example is a biological experiment where a first mix activates a freeze dried micro-organism, and a second later mix introduces a biological fixative to kill and preserve the biology (or a growth inhibitor to greatly slow the biology) hence terminating the experiment. Why might you want to do this? Imagine a biological experiment that explores whether generations of microorganisms produced entirely in microgravity have any structural differences relative to those cultured on Earth. Given that the lifetime for each generation can be very short, even just the 2-3 days of exposure to gravity from the time the payload returns to Earth until the FME is received by the student team may result in a situation where the living generation was produced entirely in a gravity environment. Introducing a biological fixative or a growth inhibitor before the FME is brought back to Earth eliminates this problem. For more information, read the Using Biologicals in SSEP Experiments: Dormant Forms, Fixatives and Growth Inhibitors document downloadable at the Document Library.
A Type 1 FME: provides a self-contained microgravity environment for an experiment that is ‘pre-loaded’ before launch, and requires no mixing of sample materials once in orbit. It may be that just exposure to microgravity is the trigger for the experiment. As an example, a selected SSEP flight experiment was designed to test if synthetic blood has the same long shelf life in microgravity as here on Earth, which is an important question for addressing medical emergencies in space. The experiment required a Type 1 FME filled with synthetic blood sitting on ISS for 4-6 weeks, and on its return to Earth assessing if it degraded as compared to synthetic blood on Earth from the same manufacturing lot.
Note on the importance of Ground Truth Experiments: a ground truth experiment is one that is identical to the experiment in orbit, except it is conducted on the ground, and at the same time the experiment is conducted in orbit. This allows the student team to do a direct comparison of the flight and ground truth experiments to assess differences due to the apparent “absence” of gravity on orbit. A ground truth experiment is almost always a vital element of microgravity experiment design given that the purpose of such experiments is to assess the impact of removing gravity from a physical, chemical, or biological system. To make such an assessment requires a comparison against a ground truth experiment that was initiated at the same time as the flight experiment. In addition, an experiment team should consider conducting multiple ground truth experiments, since this is straightforward to do, and provides more data that can be used to define an average behavior on the ground.
A ground truth is also vital in the case of an experiment that is not terminated on orbit using e.g., a biological fixative or growth inhibitor. Such an experiment will likely continue after its return to Earth, and re-exposure to normal gravity can ‘contaminate’ the results. But the duration of the experiment on ISS may be substantially longer than the up to 3 days of exposure to gravity before you receive the FME (due to landing, transport back to Houston, and possible FedExing to you). The experiment will have been carried out mostly in microgravity, but also with a short exposure time to gravity. Comparison to a ground truth allows you to assess differences due to the microgravity exposure.
6. Critical Experimental Design Constraints
Just like a professional researcher using a pre-existing laboratory or lab apparatus, you need to design your experiment to the constraints imposed by the equipment you are using and the environment in which it is to operate. Listed below are the critical design constraints you need to consider for: the Experiment Samples allowed; the FME and its operation on ISS; and how long it will take: 1) from receipt of your FME by NanoRacks in Houston to the time it arrives at ISS, and 2) from your FME’s departure from ISS until it is received by you.
6.1 Experiment Samples—Restrictions on the Fluids and Solids That You Can Use in Your Experiment
Each SSEP experiment selected for flight must pass a NASA Flight Safety Review. The review is conducted by NASA Toxicology at Johnson Space Center, and is meant to ensure that the fluids and solid materials to be used in the experiment—the Experiment Samples—pose no risk to the astronaut crew. The level of risk depends on the toxicity of the experiment samples AND how well they are contained in the mini-lab. The more “levels of containment” that are engineered into the mini-lab, the less the restrictions on the experiment samples. For each SSEP flight opportunity, NCESSE and NanoRacks work hard to ensure a high probability that each of the experiments passes Flight Safety Review. This is done by assessing the safety features engineered into the mini-lab to be used, and what restrictions this assessment imposes on allowable experiment samples.
As a benchmark of success, all of the 81 SSEP experiments selected for flight on the first 6 SSEP flight opportunities (SSEP on Shuttles Endeavour and Atlantis, and SSEP Missions 1 through 4 to ISS) passed Flight Safety Review. However, it is important to note that the final decision on whether an experiment passes the Review is NASA’s and out of the control of NCESSE and NanoRacks.
For SSEP Mission 6 to ISS, the FME mini-lab has three nested and sealed enclosures surrounding the fluids and solids to guard against an accidental release into the crew cabin. This includes the main silicone tube, together with the two polyethylene bags NanoRacks will heat seal around the tube once the flight FME arrives in Houston (see Figure 5). The FME is said to have three levels of containment, and this provides so much redundancy against an accident that virtually any fluids and solids can be used by a student team. However, the following are requirements regarding the fluids and solids used in the FME mini-lab:
a. Restricted Samples: Student teams must NOT use any of the following fluids and solids. A finalist proposal submitted to NCESSE that contains any of the substances listed below will be rejected automatically and will not move forward to the Step 2 Review Board for review.
radioactive fluids or solids
These are the only fluids and solids that NanoRacks has stated cannot be used. However, since NanoRacks and NASA reserve the right to refuse other substances or items not included in the list above based on their safety review, you are advised to consider carefully the level of hazard posed by the samples you are planning to use, even if they are not included in the list of prohibited samples above. If your experiment is making use of something that is known to be hazardous (for example, hazardous enough that there is concern that the student teams are handling these substances; or mixing may result in excess heat and/or pressure inside the tube leading to loss of containment), NCESSE advises you to alert us as soon as the potential hazard is identified as part of your experiment brainstorming so that we can have NanoRacks assess the hazard and any potential impact on NASA Flight Safety Review.
b. Human Samples: All human samples, such as blood, will need to be tested for Hepatitis B, Hepatitis C, HIV-1, HIV-2, HTLV-1, and HTLV-2. Before the selection of an experiment using human samples can be confirmed, the team must provide to NCESSE a certification letter from the sample vendor stating that tests for the presence of these viruses in the sample to be used for the flight experiment have been conducted, and the sample is free of the viruses listed above. If a vendor cannot provide the certification, the student team must arrange for these tests to be conducted in a medical laboratory, which can then provide the required certification letter.
c. Material Safety Data Sheets: Each student team is required to provide a standard Material Safety Data Sheet (MSDS) for each of their experiment samples (fluids and/or solids). An MSDS is often available from the vendor from which you purchase the sample as a downloadable PDF file. For those samples where an MSDS is not typically provided by the vendor, e.g., Tilapia fish eggs, NCESSE will provide the team the necessary guidance to submit the needed safety paperwork without undue burden. The MSDSs need not be provided when the proposals are sent for review, but they must be made available before the selection of an experiment for flight can be confirmed.
d. Specificity of Samples: Before the selection of an experiment for flight can be confirmed, each flight experiment team must provide a list of their samples with the level of specificity described in the document Required Specificity for Description of Experiment Samples, which is available for download in the Documents Library.
6.2 FME Dimensions, and Volumes for Fluids and Solids
The FME is a mini-laboratory, which means the volumes for experimental samples are small. So be sure you design an experiment with the specifications below in mind.
Each tube is 6.7 inches long (170 mm), with an outer diameter of 0.5 inches (13 mm) and an inner diameter of 3/8-inches (9.5 mm).
Type 1 FME:
Total Sealed Volume: 10.00 ml (this is volume after the two barbed stoppers are inserted in each end of the tube)
Type 2 FME:
Total Sealed Volume = Volume 1 + Volume 2: 9.2 ml (this is volume after the two barbed stoppers are inserted in each end of the tube)
Note: compared to a Type 1 FME, introduction of one clamp in the Type 2 reduces total volume by 0.8 ml
Note: minimum volume for Volume 1 or Volume 2 (achieved when a clamp is placed as close to the end of the tube as possible): 1.2 ml
Type 3 FME:
Total Sealed Volume = Volume 1 + Volume 2 + Volume 3: 8.4 ml (this is volume after the two barbed stoppers are inserted in each end of the tube)
Note: compared to a Type 1 FME, introduction of two clamps in the Type 3 reduces total volume by 2 x 0.8 = 1.6 ml
Note: minimum volume for Volume 1 or Volume 3 (achieved when a clamp is placed as close to the end of the tube as possible): 1.2 ml
Note: minimum for Volume 2 (achieved when both clamps placed as close to one another as possible): 1.9 ml
6.3 Constraints Due to the Flight Timeline for SSEP Mission 6 to ISS
Important constraints on the design of your experiment are associated with the timeline from turnover of your flight FME to NanoRacks in Houston, to when it arrives back in Houston after its flight in space. While the milestones listed below remain tentative until NASA sets precise launch and landing dates for the ferry vehicles to and from the ISS, the milestones make it possible for the student proposing teams to design their experiment with the mission timeline in mind.
The relevant critical milestones for the mission timeline for SSEP Mission 6 to ISS—
- Deadline for NanoRacks in Houston to receive your flight FME: Launch minus approximately 4 weeks
- Handover of the SSEP Payload to NASA: Launch minus approximately 3 weeks
- SSEP payload is placed aboard the ferry vehicle: Launch minus 10 days or less
- Target launch date for SSEP Payload to ISS: Current target: Mid-October 2014
- Payload transferred to ISS: Launch plus approximately 3 days
- Payload transferred from ISS to ferry vehicle; spacecraft undocking and landing: Aim is for Launch plus approximately 6 weeks
- Your FME is ready for pickup in Houston or for domestic FedExing to you overnight: Landing +(57 to 72) hours
These dates lead to the following conclusions:
a. it will take about 4.5 weeks from the time you give your flight FME to NanoRacks to the time it arrives at ISS
b. it will be on ISS for approximately 12 weeks before being transferred to the return vehicle, and the vehicle undocks for return to Earth
c. it will be 57 to 72 hours from the time the ferry vehicle undocks from ISS to when your FME is ready for pick up in Houston (or domestic FedExing to you)
d. it will be about 16 weeks from the time you give your FME to NanoRacks in Houston to it being ready for pickup in Houston (or FedExing to you) after its return from space
These conclusions likely lead to the following constraints on your experiment design:
a. Your experiment likely needs to be in stasis (in a dormant or inactive state) until it arrives on ISS. For example, if you are using biological samples, they need to be dormant until the experiment is initiatied on ISS. Some examples of dormant biological samples include: seeds; dehydrated macroscopic organisms and eggs such as brine shrimp eggs; and hundreds of freeze-dried microscopic organisms like bacteria and cells—all of which are commercially available. If the dormant biological sample is placed in one volume of the FME, the experiment can be initiated by an astronaut on ISS by unlatching the clamp and mixing the sample with a rehydration or nutrient fluid contained in the adjacent volume.
b. Dormant samples may benefit from refrigeration during transport of your flight FME from you to Houston and on to ISS. NanoRacks is arranging refrigeration for transportation of the FMEs from the moment your flight-ready FME arrives at NanoRacks to when it reaches the ISS.
At this time, NASA reports that there is no reliable refrigeration aboard the ISS.
c. Prior to the transfer of your FME to the ferry vehicle for return to Earth, you might want to terminate a biological experiment by introducing either a “fixative” which kills and preserves the biology, or by introducing a growth inhibitor which dramatically slows biological activity. This allows you to ‘shut-down’ the biology before it is re-exposed to a gravity environment for up to 2 days before you receive it in Houston (three days – or more – if FedEx overnight shipping is required from Houston to you). Terminating a biological experiment can be done in a Type 3 FME with a fixative or inhibitor in the third volume, where the appropriate clamp can be unlatched before the FME leaves ISS. For more information, read the document Using Biologicals in SSEP Experiments: Dormant Forms, Fixatives and Growth Inhibitors in the Document Library.
6.4 Thermal (Temperature) Control
There is no active temperature control within the FME. Unless you are requesting external temperature control, such as placing your FME in a refrigerator, you should expect the FME to be subjected to whatever the ambient temperature conditions might be along its route from handover of your FME to NanoRacks in Houston to return of your FME after its flight in space. While aboard ISS, you should expect the ambient conditions of the crew cabin, with a temperature of 21-24ºC (70-75°F)—a shirtsleeve environment.
SSEP is meant to offer real experiment opportunities on ISS that are interdisciplinary, and at the grade 5-12 level, intersect the science curriculum across the physical science, earth/space science, and biological science strands. That said, SSEP experiments are exceptionally well suited to biology, as long as biological samples can be maintained in a relatively dormant state until reaching ISS. While many biologicals can be kept in a dormant state at room temperature, some of them require refrigeration at a temperature of 2-8ºC. We are therefore working with NanoRacks to arrange refrigeration of the SSEP payload over much of your FME’s journey, including the following legs (unless otherwise noted):
a. shipping of your FME from you to NanoRacks in Houston: you can ship with cold packs
b. NanoRacks storage of your FME until handover to NASA: teams can request their FMEs to be refrigerated (at approximately 2-4ºC)
c. from NanoRacks handover to NASA, through loading aboard the ferry vehicle, launch, and transfer to ISS: NanoRacks has made arrangements for refrigeration on this leg.
IMPORTANT NOTE: during transport of the payload to the launch site, loading aboard the ferry vehicle, launch, and through arrival at the ISS, if any FME mini-lab requires refrigeration then the entire SSEP payload of mini-labs will be refrigerated.
d. aboard ISS over the 6 weeks your FME will be aboard ISS: NASA reports that reliable refrigeration is not available. Student teams must not count on refrigeration aboard ISS.
e. from loading aboard the return ferry vehicle, to undocking, to landing, and transport to Houston (expected duration: 24-48 hours): no refrigeration is available for this leg
f. shipping from NanoRacks in Houston to you: you can request your package be shipped with cold packs
As a result of these considerations, each experiment should be designed assuming it will be refrigerated en route to ISS. Additionally, teams requesting refrigeration during transportation to ISS, may want to have their experiment initiated shortly after arrival at ISS, given that the FMEs will be brought to room temperature on arrival, and remain at room temperature for the remainder of their stay aboard ISS.
Note that for Mission 6 to ISS, the thermal controls described above are the only ones available. For example, there will be no access to an incubator aboard the ISS, nor can any of the samples be kept frozen during transportation.
6.5 Other FME Constraints
- is translucent but there is no means to photograph samples once loaded
- has no means of active data acquisition on orbit
- has no onboard light source, and the FMEs must be stowed in an opaque payload box.
- has no provided power
7. Very Important Information for the Experimenter
Make sure to read the Designing the Flight Experiment page for how to think about framing an experiment, and an overview of the science that might be explored in microgravity. Make sure to read about the suite of Teacher and Student Resources. Make sure to get very familiar with the SSEP Mission 6 to ISS: Critical Timeline, and information on the student team proposal process on the Flight Experiment Design Competition page.