The Student Spaceflight Experiments Program (SSEP) is a United States national science, technology, engineering, and mathematics initiative that aims to increase student interest in science by offering opportunities to perform spaceflight experiments. The experiment detailed here was selected and flown aboard the third SSEP mission and the first SSEP mission to the International Space Station (ISS). Caenorhabditis elegans is a small, transparent, self-fertilizing hermaphroditic roundworm that is commonly used in biological experiments both on Earth and in Low Earth Orbit. Past experiments have found decreased expression of mRNA for several genes whose expression can be controlled by the FOXO transcription factor DAF-16. We flew a daf-16 mutant and control worms to determine if the effects of spaceflight on C. elegans are mediated by DAF-16. The experiment used a Type Two Fluids Mixing Enclosure (FME), developed by Nanoracks LLC, and was delivered to the ISS aboard the SpaceX Dragon and returned aboard the Russian Soyuz. The short time interval between experiment selection and the flight rendered preflight experiment verification tests impossible. In addition, published research regarding the viability of the FME in life science experiments was not available. The experiment was therefore structured in such a way as to gather the needed data. Here we report that C. elegans can survive relatively short storage and activation in the FME but cannot produce viable populations for post-flight analysis on extended missions. The FME appears to support short-duration life science experiments, potentially on supply or crew exchange missions, but not on longer ISS expeditions. Additionally, the flown FME was not properly activated, reportedly due to a flaw in training procedures. We suggest that a modified transparent FME could prevent similar failures in future flight experiments.
Research Containing: Space Flight
We have used the broad appeal of the universe and space flight to boost interest in science education in The Netherlands via a classroom experiment designated Seeds In Space (SIS). By germinating Rucola seeds in the dark and in the light in ground classrooms and by comparing these results with those obtained in the same experiment performed in the International Space Station (ISS) during the Dutch Soyuz mission DELTA, students could learn about the cues that determine direction of plant growth. This paper describes both the preparations that led up to the SIS experiment as well as the popular and scientific outcome. Within The Netherlands, some 80.000 students participated, representing 15% of the population in the age group of 10-14 years old. In addition, another 80.000 German pupils, a few local schools in the Moscow -Koroljov- area and some in the Dutch Antilles also participated in the SIS experiment. Considering these numbers, it can be concluded that SIS was a very successful educational project and might be considered for future space flight missions.
Several small life sciences research modules were designed to accommodate both scientific research and K-12 educational objectives on the same spaceflight mission. The K-12 educational objectives are accomplished by participating students around the globe and complimented by ground experiments conducted in their own classrooms. The spaceflight research is analyzed by students through image analysis of downlinked video and still images. The science objectives of the mission often require sample return for more detailed sample analysis on ground. Integration of new modules as part of a CGBA Science Insert (CSI) into the CGBA incubator is facilitated through standardized interfaces. Engineering challenges, trades and system architecture designs are presented for the CGBA Incubator and the CSI life sciences habitats currently on board of ISS.
We studied the growth of metal-ion silicate chemical gardens under Earth gravity (1 g) and microgravity (mug) conditions. Identical sets of reaction chambers from an automated system (the Silicate Garden Habitat or SGHab) were used in both cases. The mug experiment was performed on board the International Space Station (ISS) within a temperature-controlled setup that provided still and video images of the experiment downlinked to the ground. Calcium chloride, manganese chloride, cobalt chloride, and nickel sulfate were used as seed salts in sodium silicate solutions of several concentrations. The formation and growth of osmotic envelopes and microtubes was much slower under mug conditions. In 1 g, buoyancy forces caused tubes to grow upward, whereas a random orientation for tube growth was found under mug conditions.
Producing sprouts directly during space missions may represent an interesting opportunity to offer high-quality fresh ready to eat food to the astronauts. The goal of this work was to compare, in terms of growth and nutritional quality, rocket (Eruca sativa Mill.) seedlings grown in the International Space Station during the ENEIDE mission with those grown in a ground-based experiment (in presence and absence of clinorotation). The rocket seedlings obtained from the space-experiment were thinner and more elongated than those obtained in the ground-based experiment. Cotyledons were often closed in the seedlings grown in the space experiment. Quantitative (germination, fresh and dry weight) and qualitative (glucose, fructose, sucrose and starch) traits of rocket seedling were negatively affected by micrograv-ity, especially those recorded on seedlings grown under real microgravity conditions The total chlorophyll, and carotenoids of seedlings obtained in the space experiment were strongly reduced in comparison to those obtained in the ground-based experiment (presence and absence of clinorotation). The results showed that it is possible to produce rocket seedlings in the ISS; however, further studies are needed to define the optimal environmental conditions for producing rocket seedlings with high nutritional value.
The nematode Caenorhabditis elegans, a popular organism for biological studies, is being developed as a model system for space biology. The chemically defined liquid medium, C. elegans Maintenance Medium (CeMM), allows axenic cultivation and automation of experiments that are critical for spaceflight research. To validate CeMM for use during spaceflight, we grew animals using CeMM and standard laboratory conditions onboard STS-107, space shuttle Columbia. Tragically, the Columbia was destroyed while reentering the Earth's atmosphere. During the massive recovery effort, hardware that contained our experiment was found. Live animals were observed in four of the five recovered canisters, which had survived on both types of media. These data demonstrate that CeMM is capable of supporting C. elegans during spaceflight. They also demonstrate that animals can survive a relatively unprotected reentry into the Earth's atmosphere, which has implications with regard to the packaging of living material during space flight, planetary protection, and the interplanetary transfer of life.
Astronaut photography of cities collected during Apollo, Skylab, Shuttle, Mir, and International Space Station missions provides a useful dataset for urban analysis that complements the satellite data archive. Recent astronaut photography acquired with digital cameras is now approaching the ground resolutions of commercial satellites such as IKONOS (i.e. less than 6 m/pixel). Astronaut photographs are a relevant source of data for urban analyses, particularly for studies that do not have the resources to purchase commercial-quality data. The CCD image sensors in the cameras currently used for astronaut photography are sensitive to the infrared portion of the electromagnetic spectrum, but infrared signal is filtered out above 700 μm. As such, the digital camera data contain less information on actively synthesizing vegetation than they would with an infrared signal included. We present an analysis of aboveground biomass (i.e. actively photosynthesizing vegetation) derived from astronaut photography of the Paris, France metropolitan area acquired on April 24, 2002 using a Kodak DCS 760C electronic still camera aboard the International Space Station. The accuracy of biomass estimation obtained from the digital camera data is demonstrated by comparison with Advanced Spaceborne Thermal Emission and Reflection Radiometer visible to near infrared data for Paris acquired on April 8, 2002. Correlations of bands between the two instruments allow interpretation of the identified vegetation and soil classes. Collection of astronaut photography over global urban centers is ongoing and planned for future orbital missions, and will be a useful addition to ongoing studies of urban ecosystem change, sustainability, and resilience.
Spaceflight Effects and Molecular Responses in the Mouse Eye: Preliminary Observations After Shuttle Mission STS-133
Spaceflight exploration presents environmental stressors including microgravity-induced cephalad fluid shift and radiation exposure. Ocular changes leading to visual impairment in astronauts are of occupational health relevance. The effect of this complex environment on ocular morphology and function is poorly understood. Female 10-12 week-old BALB/cJ mice were assigned to a flight (FLT) group flown on shuttle mission STS-133, Animal Enclosure Module ground control group (AEM), or vivarium-housed (VIV) ground controls. Eyes were collected at 1, 5, and 7 days after landing and were fixed for histological sectioning. The contralateral eye was used for gene expression profiling by RT-qPCR. Sections were visualized by hematoxylin/eosin stain and processed for 8-hydroxy-2'-deoxyguanosine (8-OHdG), caspase-3, and glial fibrillary acidic protein (GFAP) and β-amyloid double-staining. 8-OHdG and caspase-3 immunoreactivity was increased in the retina in FLT samples at return from flight (R+1) compared to ground controls, and decreased at day 7 (R+7). Β-amyloid was seen in the nerve fibers at the post-laminar region of the optic nerve in the flight samples (R+7). Expression of oxidative and cellular stress response genes was upregulated in the retina of FLT samples upon landing, followed by lower levels by R+7. These results suggest that reversible molecular damage occurs in the retina of mice exposed to spaceflight and that protective cellular pathways are induced in the retina and optic nerve in response to these changes.
Exposure to microgravity during space flight affects almost all human physiological systems. The affected systems that are of key importance to human space exploration are the musculoskeletal, neurovestibular, and cardiovascular systems. However, alterations in the immune and endocrine functions have also been described. Bone loss has been shown to be site specific, predominantly in the weight-bearing regions of the legs and lumbar spine. This phenomenon has been attributed to a reduction in bone formation resulting from a decrease in osteoblastic function and an increase in osteoclastic resorption. In order to examine the effects of microgravity on cellular function here on earth, several ground-based studies have been performed using different systems to model microgravity. Our studies have shown that modeled microgravity (MMG) inhibits the osteoblastic differentiation of human mesenchymal stem cells (hMSCs) while increasing their adipogenic differentiation. Here, we discuss the potential molecular mechanisms that could be altered in microgravity. In particular, we examine the role of RhoA kinase in maintaining the formation of actin stress fibers and the expression of nitric oxide synthase under MMG conditions. These proposed mechanisms, although only examined in hMSCs, could be part of a global response to microgravity that ultimately alters human physiology. [References: 160]
Bone formation and structure have been shown repeatedly to be altered after spaceflight. However, it is not known whether these changes are related to a stress-related altered status of the corticosteroid axis. We investigated the role of corticosteroids on spaceflight-induced effects in rat pelvis and thoracic vertebrae. Thirty-six male Sprague-Dawley rats were assigned to a flight, flight control, or vivarium group (n = 12/group). Bilateral adrenalectomy was performed in six rats per group, the additional six rats undergoing sham surgery. Adrenalectomized (ADX) rats were implanted with corticosteroid pellets. On recovery from spaceflight, thoracic vertebrae and the whole pelvis were removed and processed for biochemistry, histomorphometry, or bone cell culture studies. The 17-day spaceflight resulted in decreased bone volume (BV) in the cotyle area of pelvic bones (-12%; p < 0.05) associated with approximately 50% inhibition of bone formation in the cancellous area of pelvic metaphyses and in thoracic vertebral bodies. The latter effect was associated with a decreased number of endosteal bone cells isolated from the bone surface (BS) in these samples (-42%; p < 0.05). This also was associated with a decreased number of alkaline phosphatase positive (ALP+) endosteal bone cells at 2 days and 4 days of culture, indicating decreased osteoblast precursor cell recruitment. Maintaining basal serum corticosterone levels in flight-ADX rats did not counteract the impaired bone formation in vertebral or pelvic bones. Moreover, the decreased ex vivo number of total and ALP+ endosteal bone cells induced by spaceflight occurred independent of endogenous corticosteroid hormone levels. These results indicate that the microgravity-induced inhibition of bone formation and resulting decreased trabecular bone mass in specific areas of weight-bearing skeleton in growing rats occur independently of endogenous glucocorticoid secretion.