Fig. 1: Space Shuttle Atlantis is seen docked to the Russian Space Station Mir during the first Shuttle-to-Mir docking mission in July 1995 (STS-71). This picture was taken by a Russian Cosmonaut from a Soyuz spacecraft.
Biorack is an ESA-developed multi-user facility entirely designed and devoted to biological research under microgravity conditions. It is also one of the most popular frequent flyers on NASA's Space Shuttle. Biorack flew three times on board the ESA-developed Spacehab module, first of all on the first German Spacehab mission, D-1 (61A or STS-22), in October 1985, then on the first International Microgravity Laboratory (IML-1/STS-42) which was initially planned for 1987; the Challenger disaster in January 1986, as well as various technical delays, however, did not permit IML-1 to be launched before January 1992. Biorack made its third Spacehab trip on board the second International Microgravity Laboratory (IML-2/STS-65) in July 1994. On all those missions, the variety of biological organisms flown in Biorack ranged from bacteria, yeast, cell cultures, frog and sea-urchin embryos to fruit flies, nematode worms and plant seedlings. (see Refs. 1-7)
After the IML-2 Mission, NASA and ESA agreed to fly the Biorack facility on some of the Shuttle-to-Mir Missions (S/MM), a series of US Space Shuttle flights planned to dock with the Russian Mir Space Station (Fig.1), mainly for re-supply and crew exchange. These missions permitted a permanent US presence on board Mir. They formed part of Phase One of the preparation for the International Space Station (ISS).
Fig. 1: Space Shuttle Atlantis is seen docked to the Russian Space Station Mir during the first Shuttle-to-Mir docking mission in July 1995 (STS-71). This picture was taken by a Russian Cosmonaut from a Soyuz spacecraft.
Although science was not intended to be the first priority on the S/MM missions, some limited resources were available to fly scientific instruments and facilities. During the early development phase, the Spacelab module was foreseen to be used on the S/MM missions, however NASA eventually decided to fly the McDonnel-Douglas Spacehab module (Fig.2). Initially, ten S/MM missions were planned from 1995 until the end of 1997, four of which with Biorack; however, this number was then reduced to seven missions, three of them with Biorack. Recently two S/MM missions have been added again to the list, however, Biorack will not be on board these extra flights. A single SpaceHab module was flown on the first mission (S/MM-03 or STS-76, launched on 22 March 1996), a double SpaceHab module was used on the second (S/MM-05 or STS-81, launched 12 January 1997) and third (S/MM-06 or STS-84) missions, launched on 15 May 1997.
Fig. 2: Installation of the Spacehab Module in the cargo bay of the Space Shuttle Atlantis (OV-104) on the launch pad in Kennedy Space Center. Spacehab is filled with Russian and U.S. logistics equipment for transfer to the Mir Space Station during the nine-day flight of STS-76, the third Shuttle-to-Mir Mission (S/MM-03); also located in Spacehab is ESA's Biorack facility.
NASA and ESA agreed to share evenly the available resources (stowage, incubators, centrifuges) between European and US-sponsored experiments, with a slight majority of US experiments to compensate for a previously planned, but never realised, IML-3 mission. In November 1994, a joint NASA/ESA Research Announcement (NRA 94-OLMSA-03) was released calling for experiment proposals to be sent to the respective NASA (for US experiments) or ESA (for European experiments) authorities.
Due to the short period of time between each mission, which averaged between six and nine months, compared with the more than two years preparation time between IML-1 and IML-2, and in order to reduce the risk inherent in new hardware development, the potential Principal Investigators (PIs) were asked to make use, as much as possible, of Recommended Experiment Hardware which had been presented in the NRA. These already developed pieces of hardware had previously been flown on the earlier Biorack/Spacelab missions and were selected for their reliability, user-friendliness and easy crew interface, and their relevance with respect to particular scientific fields. Typical hardware for bacterial or mammalian cell cultures, with or without medium exchange, small embryos, small insects and plant seedlings were recommended. However, since each experiment sometimes has highly-specific requirements for biocompatibility, some minor internal modifications to the recommended hardware were possible.
The ESA experiments selected also had to fall within the 'Focus Science' fields specified for biological investigation by ESA's Life Sciences Working Group (LSWG) and Microgravity Advisory Committee (MAC) and approved by ESA's Microgravity Programme Board:
Also, potentially new research topics in biology, such as programmed cell death (apoptosis), long-term genetic stability, developmental neurobiology, and cell-nucleus organisation were identified to be of high scientific interest.
In March 1995, the ESA and NASA science peer groups reviewed the received proposals which, after having been evaluated and approved or rejected according to their scientific merit, were passed on to the Biorack technical accommodation study team which then released a core experiment list and a reserve experiment list for the S/MM-05 and S/MM-06 missions.
For the first mission however, the time constraints were even tighter, since STS-76 (S/MM-03) was scheduled for launch in March 1996. Therefore, it was decided that the NRA will not be applicable for experiment selection on this first mission, but only for S/MM-05 and S/MM-06. In order to speed up the selection process for S/MM-03, it was agreed to either re-fly some IML-1 or IML-2 experiments, or to fly some experiments which had already been selected for missions that had then been cancelled, e.g. the BioKit , which should have flown on the Euromir missions, or the pre-selected experiments for the Spacelab Columbus Precursor Flights. On NASA's side, it was decided to choose from experiment proposals which had been received for the Small Payloads Research in Space Life Sciences programme. Nevertheless, the selected S/MM-03 experiments had to be compatible, as far as possible, with the recommended hardware.
The experiment-specific hardware had to fit into the Biorack standard containers, most of them use Type I containers (internal dimensions: 81 x 40 x 20 mm, useful volume of approximately 65 ml) while a few larger pieces of hardware had to be accommodated inside Type II containers (internal dimensions: 87 x 63 x 63 mm, useful volume of approximately 345 ml). Some Type II containers (Type II/E) were equipped with an electrical connector to receive power from the Biorack and to allow data downlink (BIOREACTOR on S/MM-03 and DOSTEL on S/MM-05 and S/MM-06). For the three Shuttle-to-Mir missions, the Biorack containers were distributed as follows:
S/MM-03:
Type I containers: 111
ESA: 54 exp. containers + 7
temperature recorders + 2 dummies
NASA: 48 exp. containers
Type II containers: 7
ESA: 7, including 2 Type II/E
NASA: 0
S/MM-05:
Type I containers: 104
ESA: 60 exp. containers + 7
temperature recorders + 2 dummies
NASA: 32 exp. containers
Type II containers: 19
ESA: 5, including 1 Type II/E
NASA: 14
S/MM-06:
Type I containers: 103
ESA: 45 exp. containers + 7
temperature recorders + 2 dummies
NASA: 49 exp. containers
Type II containers: 22
ESA: 4, including 2 Type II/E
NASA: 18
The crew time needed to perform all Biorack experiment activities was about 21 hours for S/MM-03,
and about 23 hours for both S/MM-05 and S/MM-06, as shown below.
S/MM-03:
ESA experiments: 355 minutes
NASA experiments: 760 minutes
Facility operations: 170 minutes
Total: 1285 minutes (21h: 25 min)
S/MM-05:
ESA experiments: 780 minutes
NASA experiments: 490 minutes
Facility operations: 125 minutes
Total: 1395 minutes (23h: 15 min)
S/MM-06:
ESA experiments: 517 minutes
NASA experiments: 768 minutes
Facility operations: 122 minutes
Total: 1407 minutes (23h: 27 min)
Experiments, for the three S/MM Missions, with relevant scientific fields and Principal Investigator name are listed in Table 1. It has to be noted that, on S/MM-03, an additional experiment (24-F URCHIN), which was on the reserve list for the 22°C incubator, was added to the mission only a few weeks before launch due to a change in the launch stowage configuration; for practical reasons, it was decided to include the simple transfer operations of this experiment in FO-10 BIO-FAC, therefore URCHIN does not appear in Table 1. This experiment (PI: Dr. Hans-Jurg Marthy, CNRS, Banyuls-sur-Mer, France) was investigating the sea urchin larva as a model for studying biomineralisation and demineralisation processes in Space.
Nine experiments (3 NASA, 6 ESA) were flown on S/MM-03, eleven (5 NASA, 6 ESA) on S/MM-05 and ten (4 NASA, 6 ESA) on S/MM-06, bringing to a total of 30 the number of experiments on the three Shuttle-to-Mir missions.
The Core Biorack configuration selected for flight on the three S/MM Missions, is basically the D-1 and IML-2 configuration, with two incubators, incubator A, set at 22°C and incubator C, set at 37°C and the Glovebox (see Figs. 3, 4 & 5). However, two major differences are noticeable: there is no active cooling device and there is very limited experiment stowage possibility for containers or ancillary equipment inside the Spacehab module itself. For special and relatively voluminous equipment, like the CNES-developed Photobox, a dedicated soft stowage location was made available in Spacehab. Everything else had to be accommodated in three Middeck Locker Stowage Inserts (MLSIs) in the Shuttle Middeck, two of them carrying a +5°C Passive Thermal Control Unit (PTCU), in addition of ambient foam racks, and the third one being composed of two half-inserts with ambient foam trays. To avoid inconvenient and frequent crew trips to and from the middeck during flight operations, the PTCUs and the foam racks were installed in the Spacehab Module (see Fig. 6) once in orbit and returned to the Middeck prior to landing. Because of the absence of any active cooler, samples which have to be returned to ground at +5°C have to be loaded directly from Incubator A, Incubator C or the Glovebox into one of the two +5°C (PTCU). Although loading containers from a +37°C or +22°C environment directly in a PTCU may reduce the useful lifetime of the Phase Change Material (PCM) used in the PTCU, the temperature could be kept within the given limits for 20 days. Samples needing to be frozen had to be loaded and returned in the NASA-provided LSLE Freezer (-20°C).
Fig. 3: The Biorack resources in the Space Shuttle Atlantis, as configured for the S/MM-03 (STS-76) mission.
Fig. 4: Biorack as installed in the Spacehab single module during the S/MM-03 flight: two incubators (22°C and 37°C) above and below the glovebox provided the thermal environment and 1-g reference centrifuges for the experiments. NASA's LSLE Freezer (lower left) accommodated frozen samples. A lap-top computer was used as an interface for facility and experiment data. The camcorder (top) allowed on-line video observation or recordings of the glovebox activities.
Fig. 5: Astronaut Ron Sega removes a Type II experiment container from Incubator A (22°C) for sampling inside the glovebox during the S/MM-03 flight.
Fig. 6: Biorack experiment containers, housed in +5°C Passive Thermal Conditioning Units (PTCU's) and ambient foam racks, are installed by Astronauts John Grunsfeld and Jeff Wisoff in the Spacehab double module during the S/MM-05 flight.
In addition to this basic equipment, an LSLE back-up -10°C PTCU, carried in a fourth MLSI, was flown on the S/MM-05 mission, and an experimental Inflatable Thermal Control Unit (ITCU) was tested on S/MM-06.
The back-up -10°C PTCU flown on S/MM-05 was also used to carry various frozen biological samples to assess the impact of long-term frozen stowage on viability and other basic properties of biological organisms. Results may help planning future biological experiments on the International Space Station (ISS), by determining if medium-freezing (-20°C) for long periods is safe enough to preserve the functional integrity of the samples, or if deep-freezing (-80°C) which is much more power-consuming and expensive, is indeed necessary. A variety of organisms provided by several investigators was used for this experiment: osteoblasts, lymphocytes, bacteria, sea-urchin sperm, etc.
Nematode worms and rotifers were stowed for a similar investigation in a dry state at ambient temperature during this flight.
Most of the Biorack experiment flight operations were completed nominally during the STS-76 Mission, however, due to technical problems with one of the orbiter's Auxiliary Power Units (APU), the mission was shortened by one day. This meant that a major re-planning of the remaining Biorack activities became necessary. One sampling session of the Bioreactor experiment had to be deleted.
Although at the time of preparing this article, Principal Investigator teams were still processing their samples and data, a few first-look results have already been presented. Among these, some results from the OSTEO experiment are particularly interesting because they are unexpected: they indicate that activation of some of the genes that code for key enzymes involved in the bone tissue mineralisation process may actually be increased under microgravity conditions. This appears not to agree with earlier observations that astronauts' bones do lose calcium in space, especially during long-duration space flights. Follow-on experiments, OSTEOGENE flown on S/MM-05 and OSTEOMARS on S/MM-06 may help to clarify those seemingly contradictory facts.
The Space Shuttle Atlantis was launched on time, on 12th January 1997, and the flight was nominal until landing at KSC on January 22nd. However, the late announcement of a 24-hour delay of the Rendez-vous and Docking with Mir (dictated by a change of the Mir Station's orbital elements), necessitated the re-planning of Biorack's experiments. Nevertheless, most experiments were completed nominally (Fig.7) and some of them are even expected to produce more scientific results than anticipated. However, some inadequate handling of the additional frozen samples (-20°C long-towage test) after the flight jeopardised the scientific output of this test due to unforeseen significant variations of the samples' temperatures during the few hours following landing.
Fig. 7: Astronaut Jeff Wisoff prepares lentil seedlings for final treatment after exposure to different accelerations on a mini-centrifuge and subsequent time-lapse photography in a photobox (Biorack experiment 89-F GRAVITY by G. Perbal, Paris) during S/MM-05.
Once again, Atlantis lifted off on time, at the very first second of a 7-minute launch window, at 4:07 am EDT, on 15 May 1997, beginning the sixth and last flight of ESA's Biorack facility. STS-84 was truly an international mission, with crew members from various nationalities (Figure 8), origins and cultures thereby giving a pre-taste of what will be life and operations on board the International Space Station. ESA astronaut Jean-François Clervoy (Figure 9) together with NASA Mission Specialist Edward T. Lu and Russian Cosmonaut Elena Kondakova performed most of the Biorack experiments on this flight. Atlantis landed on KSC Shuttle Landing Facility runway on 24 May 1997 at 9:28 am after completion of 145 orbits around the Earth.
Fig. 8: The STS-84 crew in front of the complete set of Biorack experiment hardware used for the S/MM-06 flight. From right to left: Eileen M. Collins (Pilot), Carlos I. Noriega (Mission Specialist), Edward T. Lu (Mission Specialist), Elena Kondakova (Mission Specialist, Russian Cosmonaut), Charles J. Precourt (Mission Commander), Jean-François Clervoy (Mission Specialist and Payload Commander, ESA Astronaut), Julia Bateman (Russian Interpreter). Not in the picture is C. Michael Foale who was carried up to Mir where he replaced Jerry M. Linenger (brought to Mir with STS-81, S/MM-05 in January 1997) who returned to Earth with the STS-84 crew.
Fig. 9: ESA Astronaut Jean-François Clervoy (Mission Specialist 1 and Payload Commander on STS-84) working on one of the Biorack experiments in the Glovebox.
Although the crew only had limited time available on docking day (FD-3) and the logistics had to be reshuffled for the PLASTID experiment, all experiments were completed nominally. According to first preliminary reports from the Principal Investigators, all of them expect a 100% science output from their experiments. However, the flight test of the Inflatable Thermal Control Unit (ITCU) did not fully meet the expectations since the unit did not reach the pre-set consigned temperatures; nevertheless, inflation and deflation of the ITCU were achieved nominally.
References:
Note: A special issue of "Journal of Biotechnology" (published by Elsevier) has been entirely dedicated to 'Biology Under Microgravity Conditions in Spacelab
IML-2'. This issue (Volume 47, Nos. 2,3, dated 27 June 1996) includes the results of most of the BIORACK and NIZEMI experiments.
ESA Microgravity News Vol. 10 No. 2