SporeSat Nanosatellite Mission
SporeSat is an autonomous, free-flying 3U CubeSat that will be used to conduct scientific experiments to gain a deeper knowledge of the mechanisms of plant cell gravity sensing. SporeSat is being developed through a partnership between NASA/ARC (Ames Research Center), Moffett Field, CA, and the Department of Agricultural and Biological Engineering at Purdue University (PU), West Lafayette, Indiana. The Purdue University PIs (Principal Investigators) are Amani Salim (postdoctoral research assistant) and Prof. Jenna L. Rickus. Science collaborators on the project include: Joon Park at Purdue University, Stanley Roux at the University of Texas at Austin, and Purdue alumna Brittany Wickizer at the NASA Ames Research Center. 1) 2) 3) 4)
Figure 1: Illustration of a single C. richardii spore (left) and photo of calcium ion measurement microelectrodes on either side of a single spore (right), image credit: NASA, PU
NASA/ARC is responsible for overall management of the hardware development to include the thermal, power, electrical, and mechanical subsystems of the payload, including the mini centrifugal subsystems; integration and test of the payload, and for interfacing the payload with an upgraded nanosatellite spacecraft with updated flight software. NASA Ames is also the lead in the design, fabrication and testing of the payload elements.
The mission is funded as part of the Space Biology Project at NASA/ARC. Funding for Space Biology comes from the Space Life and Physical Sciences Research and Applications Division within the Human Exploration and Operations Mission Directorate at NASA Headquarters.
SporeSat is a 3U CubeSat of size 10 cm x 10 cm x 34 cm with a mass of 5.5 kg. SporeSat utilizes flight-proven spacecraft technologies demonstrated on prior ARC nanosatellite missions, such as PharmaSat and O/OREOS (Organism/Organic Exposure to Orbital Stresses) as well as upgrades that increase the hardware integration capabilities with SporeSat science instrumentation. In addition, the SporeSat science payload will serve as a technology platform to evaluate new microsensor technologies for enabling future fundamental biology missions. 5)
The satellite attitude is controlled by permanent magnets and hysteresis rods that dampen the rotational energy.
Figure 2: Photo of the SporeSat nanosatellite (image credit: NASA)
Figure 3: Exploded view of the SporeSat (image credit: NASA)
• Three main PCBs – EPS, C&DH, and Backplane
• Leveraging heritage from previous missions .....but now:
- Faster CPU - PIC32
- RTOS Micrium µC/OS-II
- Memory microSD (2 GB), and 3Mbit FRAM
- Self tracking ICs on every PCB
- One-wire interface
- 5 line switches for payloads (2A each)
- Bus draws less than 50 mA (without radios)
- 2 radios - 1 Microhard 2420, 1 Stensat beacon
- Passive attitude control magnet and hysteresis rod
- Fixed body mounted triple junction solar panels
- 80 Whr battery.
Figure 4: Overview of the flight software (image credit: NASA/ARC)
RF communications: S-band and Amateur radio communications in UHF/VHF. The S-band link uses the commercial Microhard MHX-2420 COTS transceiver. The UHF frequency is operating at 437.100 MHz FM (modulation: AFSK), the SporeSat beacon sends an AX.25 packet every 5 seconds. 6)
Mission operations will be conducted at SCU (Santa Clara University), Santa Clara, CA and at NASA/ARC. 7)
Launch: The SporeSat 3U CubeSat was part of the secondary payloads on the Dragon cargo capsule resupply space transport mission to the ISS, the CRS-3 (Cargo Resupply Services-3) Falcon-9v.1.1 mission, launched on April 18, 2014 of SpaceX. The launch site was Cape Canaveral, FL. 8)
SporeSat was competitively selected for NASA’s CubeSat Launch Initiative in 2012 and is manifested on the SpaceX CRS-3 launch from Cape Canaveral.
Orbit: Near-circular orbit, altitude of ~400 km of the ISS, inclination =51.6°.
Secondary payloads: The secondary payloads (4 nanosatellites and 1 CubeSat) were contained in four P-PODs (Poly Picosatellite Orbital Deployers) and installed on the second stage of the Falcon 9 launcher. These secondary payloads were not being delivered to the ISS, but released from their P-PODs following the separation of the Dragon capsule from the second stage (~10.5 minutes after liftoff). The insertion orbit of the secondary payloads was at an altitude of ~325 km with an inclination of ~51.6º. 9)
The secondary payloads were part of the fifth installment of NASA's ELaNa (Educational Launch of Nanosatellite) mission. Over 120 students have been involved in the design, development and construction of all the CubeSats that were flown as auxiliary payloads on the SpaceX-3 cargo resupply mission. 10)
• KickSat, a 3U CubeSat of Cornell University, N.Y., USA. KickSat will carry and attempt to deploy about 250 femtosatellites into LEO (Low Earth Orbit).
• All-Star/THEIA, a 3U CubeSat of COSGC (Colorado Space Grant Consortium).
• SporeSat, a 3U CubeSat (~5.5 kg) developed through a partnership between NASAs Ames Research Center and the Department of Agricultural and Biological Engineering at Purdue University. SporeSat will be used to conduct scientific experiments to gain a deeper knowledge of the mechanisms of plant cell gravity sensing.
• TSAT (TestSat-Lite), a 2U CubeSat developed at Taylor University of Upland, Indiana. The objective is to perform measurements of the temperature and density of the plasma in the near-Earth space environment.
• PhoneSat-2.5, a technology 1U CubeSat of NASA/ARC to continue technology demonstrations of the PhoneSat CubeSat series.
• April 25, 2014: The “SporeSat Mission Dashboard” is reporting ( 6 days into the mission) that SporeSat was properly deployed and stabilization of the nanosatellite is ongoing. The orbital life of SporeSat is estimated to be between 30-60 days. 11)
Sensor complement: (Space biology science experiment)
Understanding how gravity impacts plants is key for determining the conditions necessary to grow plants in space. Being able to grow plants for food in microgravity and space environments is crucial if we're going to reach this amazing future of long-term space exploration that we all imagine. We tend to think of propulsion and spacecraft technology as the main challenges to space exploration, but the true challenge is really the biology. 12)
The objective of the free-flying spacecraft is to investigate how variations in gravity affect calcium signaling in germinating spores of the fern Ceratopteris richardii. Calcium signaling - a gravity-directed process - acts as a compass for plants, determining the directions sprouts and roots grow during germination.
The experiment will help determine the minimum level of gravity needed to trigger normal calcium signaling activity in plant cells. Artificial gravity might be necessary to produce crops for food on future long-term space missions. The study also will lead to a more detailed understanding of the molecular and biophysical mechanisms plants use to detect gravity.
The Investigators at Purdue University are responsible for development of the science payload, specifically the lab-on-a-chip device that supports and measures the fern spore ion channel activity and, in collaboration with NASA/ARC, for measurement electronics circuit board assemblies.
Figure 5: SporeSat satellite transparent-composite showing the science payload; three lab-on-a-chip devices - bioCDs (image credit: NASA, PU)
SporeSat’s space biology science experiment will investigate the effect of gravity on the reproductive spores of the fern, Ceratopteris richardii. Some plants, including C. richardii, use gravity to determine direction and to guide their roots to grow down into the earth where they find nutrients for growth. Calcium is important to overall plant growth and development, but it also plays a role in the process of sensing gravity and signaling the response of downward plant growth. To better understand the role of the on/off modulation of cellular calcium ion channels in gravity sensing, the SporeSat experiment will measure the effect of different artificial gravity levels on calcium concentrations that result from the opening and closing of these channels.
Specifically, the SporeSat experiment will utilize three lab-on-a-chip devices, called “bioCDs”, that integrate the sensors that allow for real-time measurement of calcium signaling at each of the variable gravity treatments planned for the experiment.
Each bioCD contains four rings of eight fern spores. During the experiment, two of the bioCDs will spin to simulate gravity, while the third will remain stationary as a microgravity control. The two bioCDs are equipped with a motor to provide artificial (centrifugal) gravity at pre-determined levels.
Since human cells use calcium signaling, the study also is an important step toward understanding the effects of space's microgravity on the human body.
Figure 6: Exploded view and photo of prototype of the Lab-on-a-Chip (bioCD) Rotating Assembly that contains and measures the fern spores (image credit: PU, NASA)
Figure 7: Assembling the bioCD measurement electronics (image credit: NASA/ARC, PU, Ref. 3)
Figure 8: Integrating the bioCD rotating assembly and motor (image credit: NASA/ARC, PU)
Figure 9: Three bioCDs are contained in two rotating assemblies and one Standby Assembly (TVPM), image credit: NASA, Dominic Hart 13)
In conclusion (Ref. 3):
• Sophisticated science experiments can be implemented in small spacecraft to study phenomena uniquely accessible in the outer space environment.
• The project will use SporeSat to study the gravity response of ion channels, particularly at low (sub-terrestrial) gravity levels that cannot be simulated on Earth.
- The SporeSat experiment measures the responses of Ca2+ ion channels, which are common to many forms of biology, including humans.
• Ion channels control how ions like sodium, potassium, and calcium move in and out of cells: they are a means of regulation and control for cells.
- Ion channels control our heart rhythm and blood pressure
- Ion channels help some plants — for example the fern spores that are onboard SporeSat — figure out which way is up, so they send their roots and shoots in the right directions
• SporeSat results will link modulation of Ca2+ ion channel activity to the level of gravitation for fern spores
• SporeSat is a first-of-its-kind small science satellite that couples novel miniaturized technology to novel biological science: a variable-rate centrifuge allows testing the response of Ca2+ ion channels from microgravity to hypergravity!
1) Andres Martinez, Gelsomina Cappuccio, David Tomko, “SporeSat - Investigating the Gravitational Threshold for Calcium Ion Channel Activation using a Nanosatellite Platform-Based Lab-on-a-Chip,” 2013, NASA, URL: http://www.nasa.gov/centers/ames/engineering/projects/sporesat.html#.U0J-C6KegkA
3) Andres Martinez, “SporeSat,” Proceedings of the 11th Annual CubeSat Developers’ Workshop - The Edge of Exploration,” San Luis Obispo, CA, USA, April 23-25, 2014, URL: http://www.cubesat.org/images/cubesat/presentations/Developers-Workshop2014/Martinez_SPORESAT.pdf
9) Patrick Blau, “Dragon SpX-3 Cargo Overview,” Spaceflight 101, URL: http://www.spaceflight101.com/dragon-spx-3-cargo-overview.html
10) “ELaNa V CubeSat Launch on SpaceX-3 Mission,” NASA Facts, March 2014, URL: http://www.nasa.gov/sites/default/files/files/ELaNa-V-Factsheet-508.pdf
12) “Purdue study to measure gravity's effects on plant cells in space,” Purdue, April 10, 2014, URL: http://www.purdue.edu/newsroom/releases/2014/Q2/purdue-study-to-measure-gravitys-effects-on-plant-cells-in-space.html
13) Andres Martinez, Jeffrey D. Smith, David Tomko, “SporeSat - Investigating the Gravitational Threshold for Calcium Ion Channel Activation using a Nanosatellite Platform-Based Lab-on-a-Chip,” NASA Facts, FS-2014-03-04-ARC, URL: http://www.nasa.gov/sites/default/files/sporesat_factsheet_031214.pdf
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).