RAX-2

Last updated
Radio Aurora Explorer 2
The RAX-2 Spacecraft.jpg
RAX-2 under construction
Mission typeAuroral research
Operator SRI International
University of Michigan
COSPAR ID 2011-061D OOjs UI icon edit-ltr-progressive.svg
SATCAT no. 37853
Spacecraft properties
Spacecraft type 3U CubeSat
Start of mission
Launch date28 October 2011, 09:48:02 (2011-10-28UTC09:48:02Z) UTC
Rocket Delta II 7920-10C
Launch site Vandenberg SLC-2W
Contractor United Launch Alliance
End of mission
Last contact10 April 2013 (2013-04-11)
Orbital parameters
Reference system Geocentric
Regime Low Earth
Semi-major axis 6,964.69 kilometers (4,327.66 mi) [1]
Eccentricity 0.0203467 [1]
Perigee altitude 451 kilometers (280 mi) [1]
Apogee altitude 735 kilometers (457 mi) [1]
Inclination 101.71 degrees [1]
Period 96.41 minutes [1]
Epoch 24 January 2015, 22:19:36 UTC [1]
 

RAX-2 (Radio Aurora Explorer 2) is a CubeSat satellite built as a collaboration between SRI International and students at the University of Michigan College of Engineering. It is the second spacecraft in the RAX mission. The RAX-1 mission ended after approximately two months of operation due to a gradual degradation of the solar panels that ultimately resulted in a loss of power. RAX team members applied the lessons learned from RAX-1 to the design of a second flight unit, RAX-2, which performs the same mission concept of RAX-1 (launched in November 2010) with improved bus performance and additional operational modes. Science measurements are enhanced through interactive experiments with high power ionospheric heaters where FAI will be generated on demand.

Contents

RAX-2 was launched from Vandenberg Air Force Base in October 2011 atop a Delta II rocket.

Spacecraft design

With the exception of the solar panels, the designs of RAX-1 and RAX-2 are largely identical. RAX-1 and RAX-2 are standard 3U CubeSats with physical dimensions of approximately 10 cm x 10 cm x 34 cm and approximate mass of 3 kg. The satellites conform to the 3U CubeSat standard such that they can be launched from the Cal Poly P-POD, a specialized container and deployment mechanism by engineers at Cal Poly San Luis Obispo that many launch providers are able to attach as secondary payloads to their launch vehicles.

Design strategy

The general design strategy for RAX was to make use of commercial off-the-shelf (COTS) components to reduce development time and cost. Several of RAX's subsystems consist of a central commercial component with support electronics (power, bus communication, switches, etc.) built around it. However, there were many instances where subsystems needed to be designed from the ground up because COTS solutions did not meet mission requirements. While these instances cost the team a great deal of time and funds, the benefit was the development of in-house expertise for building customizable systems for future Michigan missions. Please see the subsystems section below for specific design details.

Design implementation

RAX is divided into seven subsystems, one payload, 15 total circuit boards, 7 microprocessors, and two FPGAs. The subsystem boards are designed around the PC-104 standard so that each board plugs into another at the 104-pin header from the base of the satellite up to the payload. From there, individual interconnects run from the electronics stack to the payload receiver. Aluminum rails run through each corner of the board, and threaded standoffs are located above and below to lock each board in place. The four long sides of the satellite are covered with eight solar cells each, leaving the top and bottom panels open for the communication and GPS antennas. [2]

RAX-2 is a stack of three standard 'CubeSat' modules weighing about 3 kg. The flight computer is a Texas Instruments MSP430-based while the processing of scientific data is done with a 520 MHz PXA270. Communications are by means of a UHF transceiver with downlink speeds of 38.4 kbit/s, and an S-band downlink for scientific data that provides 115.2 kbit/s downlink.

Mission overview

The Delta II carrying RAX-2, five other CubeSats, and the NPP Earth observing satellite, launching from Vandenberg AFB on 28 Oct 2011 The Delta 2 carrying RAX-2, five other CubeSats, and the NPP Earth observing satellite, launching from Vandenberg AFB on 28 Oct 2011..jpg
The Delta II carrying RAX-2, five other CubeSats, and the NPP Earth observing satellite, launching from Vandenberg AFB on 28 Oct 2011

The primary mission objective of RAX-2 is to study large plasma formations in the ionosphere, the highest region of our atmosphere. These plasma structures, a form of turbulence called field-aligned irregularities (FAIs), can distort communication and navigation signals such as global positioning systems (GPS).

To study FAI, the RAX mission will utilize a large incoherent scatter radar in Poker Flats, Alaska (known as PFISR). PFISR will transmit powerful radio signals into the plasma instabilities that will be scattered into space. During that time, the RAX spacecraft will be orbiting overhead and recording the scatter signals with an onboard receiver. These signal recordings will be processed by an onboard computer and transmitted back to our ground stations where scientists will analyze them. The goal of this one-year science mission is to enhance our understanding of FAI formation so that short-term forecast models can be generated. This will aid spacecraft operators with planning their mission operations around periods of expected communication disruption.

RAX-2 builds on the RAX-1 heritage to continue the scientific mission; it is a reflection of students learning from experience, and implementing new, more inventive technologies firsthand. RAX-2 was developed to correct the power failure and enable scientific experiments at regular intervals.

Launch

RAX-2 launched on October 28, 2011, [3] as a secondary payload on NASA's NPP (NPOESS Preparatory Project) mission. The CubeSat launch was sponsored by NASA as part of the ELaNa-3 program. [4] [5] [6] [7] It launched from Vandenberg Air Force Base in central California on a United Launch Alliance Delta II rocket, flying in the 7920-10 configuration. [8] CubeSat separation occurred 98 minutes after launch, and beacons from RAX-2 were heard shortly thereafter.

This was a multi-payload mission with five other CubeSats, M-Cubed, AubieSat-1, DICE-1, DICE-2, and Explorer-1.

Mission science

The objective of the RAX mission is to understand the microphysics that lead to the formation of magnetic field-aligned plasma irregularities (FAI), an anomaly known to disrupt communications with orbiting spacecraft. The RAX mission is specifically designed to remotely measure, with extremely high angular resolution, the 3-D k-spectrum (spatial Fourier transform) of ~1 m scale FAI as a function of altitude, in particular measuring the magnetic field alignment of the irregularities. [9]

The RAX mission will use a network of existing ground radars that will scatter signals off the FAI to be measured by a receiver on the RAX spacecraft. The spacecraft will measure "radio aurora", or the Bragg scattering from FAI that are illuminated with a narrow beam incoherent scatter radar (ISR) on the ground. This remote sensing method is based on the powerful mathematical relation that the radio aurora intensity is proportional to the irregularity k-spectrum evaluated at the Bragg wave number. [10]

The ground-to-space bistatic radar experiment highly resolves the k-spectrum, which means that the sensed volume of plasma is homogeneous and that the received signal contains a pure content of wave vectors, which are important for accurate analysis of wave growth and damping. Moreover, each experiment will be tagged with the convection electric field Ec, a principal driver of the irregularities, which will be measured (besides altitude profiles of plasma density and temperatures) by the ISR during an experiment. [11]

The RAX mission is a unique opportunity to quantify plasma processes in a homogeneously resolved volume of plasma with the driving force and the effect measured effectively simultaneously.

Scientific discoveries and original experimental research

RAX-2 successfully made the first-ever measurement of naturally occurring auroral turbulence recorded using a nanosatellite radar receiver. The distinctive radar echoes recorded on March 8 were taken with the Radio Aurora Explorer (RAX) CubeSat. The RAX nanosatellite measured turbulence over Fairbanks, Alaska that was a direct result of a geomagnetic storm triggered by the largest solar flare in the past five years. The Earth's high latitude ionosphere, a region of the upper atmosphere associated with solar-driven aurora or "northern lights," becomes highly unstable when large currents flow during geomagnetic storms. RAX was specifically designed by SRI and the University of Michigan to measure this auroral turbulence from an orbital vantage point inaccessible to traditional ground-based radars. [12]

"The RAX radar echo discovery has convincingly proved that miniature satellites, beyond their role as teaching tools, can provide high caliber measurements for fundamental space weather research," said Therese Moretto Jorgensen, Ph.D., Geospace program director in the Division of Atmospheric and Geospace Sciences at the National Science Foundation. [13]

See also

Related Research Articles

<span class="mw-page-title-main">CubeSat</span> Miniature satellite in 10 cm cube modules

A CubeSat is a class of small satellite with a form factor of 10 cm (3.9 in) cubes. CubeSats have a mass of no more than 2 kg (4.4 lb) per unit, and often use commercial off-the-shelf (COTS) components for their electronics and structure. CubeSats are deployed into orbit from the International Space Station, or launched as secondary payloads on a launch vehicle. As of December 2023, more than 2,300 CubeSats have been launched.

<span class="mw-page-title-main">IMAGE (spacecraft)</span> NASA satellite of the Explorer program

IMAGE is a NASA Medium Explorer mission that studied the global response of the Earth's magnetosphere to changes in the solar wind. It was believed lost but as of August 2018 might be recoverable. It was launched 25 March 2000, at 20:34:43.929 UTC, by a Delta II launch vehicle from Vandenberg Air Force Base on a two-year mission. Almost six years later, it unexpectedly ceased operations in December 2005 during its extended mission and was declared lost. The spacecraft was part of NASA's Sun-Earth Connections Program, and its data has been used in over 400 research articles published in peer-reviewed journals. It had special cameras that provided various breakthroughs in understanding the dynamics of plasma around the Earth. The principal investigator was Jim Burch of the Southwest Research Institute.

<span class="mw-page-title-main">Small satellite</span> Satellites of low mass and size, usually under 500 kg

A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under 1,200 kg (2,600 lb). While all such satellites can be referred to as "small", different classifications are used to categorize them based on mass. Satellites can be built small to reduce the large economic cost of launch vehicles and the costs associated with construction. Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, gathering of scientific data and radio relay. Technical challenges in the construction of small satellites may include the lack of sufficient power storage or of room for a propulsion system.

<span class="mw-page-title-main">Poker Flat Research Range</span>

The Poker Flat Research Range (PFRR) is a launch facility and rocket range for sounding rockets in the U.S. state of Alaska, located on a 5,132-acre (20.77 km2) site at Chatanika, about 30 miles (50 km) northeast of Fairbanks and 1.5 degrees south of the Arctic Circle. More than 1,700 launches have been conducted at the range to study the Earth's atmosphere and the interaction between the atmosphere and the space environment. Areas studied at PFRR include the aurora, plasma physics, the ozone layer, solar proton events, Earth's magnetic field, and ultraviolet radiation. Rockets launched at PFRR have attained an apogee of 930 miles (1,500 km).

The Space Test Program (STP) is the primary provider of spaceflight for the United States Department of Defense (DoD) space science and technology community. STP is managed by a group within the Advanced Systems and Development Directorate, a directorate of the Space and Missile Systems Center of the United States Space Force. STP provides spaceflight via the International Space Station (ISS), piggybacks, secondary payloads and dedicated launch services.

The Canadian Advanced Nanospace eXperiment (CanX) program is a Canadian CubeSat nanosatellite program operated by the University of Toronto Institute for Aerospace Studies, Space Flight Laboratory (UTIAS/SFL). The program's objectives are to involve graduate students in the process of spaceflight development, and to provide low-cost access to space for scientific research and the testing of nanoscale devices. The CanX projects include CanX-1, CanX-2, the BRIght Target Explorer (BRITE), and CanX-4&5.

<span class="mw-page-title-main">PharmaSat</span>

PharmaSat was a nanosatellite developed by NASA Ames Research Center which measured the influence of microgravity upon yeast resistance to an antifungal agent. As a follow on to the GeneSat-1 mission, the Ames Small Spacecraft Division conducted the PharmaSat mission in collaboration with industry and local universities.

<span class="mw-page-title-main">DRAGONSat</span>

DRAGONSat is a pair of nanosatellites that will be demonstrating autonomous rendezvous and docking (ARD) in low Earth orbit (LEO) for NASA. It will be gathering flight data with a global positioning system (GPS) receiver strictly designed for space applications to gather flight data in the space environment. ARD is the capability of two independent spacecraft to rendezvous in orbit and dock without crew intervention. One DRAGONSat was built by the University of Texas and the other one was built by Texas A and M University, the Space Shuttle Payload Launcher (SSPL), These satellite projects will rendezvous and dock with each other in space without the benefit of human intervention.

ITUpSAT1, short for Istanbul Technical University picoSatellite-1, is a single CubeSat built by the Faculty of Aeronautics and Astronautics at the Istanbul Technical University. It was launched on 23 September 2009 atop a PSLV-C14 satellite launch vehicle from Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh in India, and became the first Turkish university satellite to orbit the Earth. It was expected to have a minimum of six-month life term, but it is still functioning for over two years. It is a picosatellite with side lengths of 10 centimetres (3.9 in) and a mass of 0.990 kilograms (2.18 lb).

<span class="mw-page-title-main">Radio Aurora Explorer</span>

Radio Aurora Explorer (RAX) is the first National Science Foundation sponsored CubeSat mission. The RAX mission is a joint effort between SRI International in Menlo Park, California and the University of Michigan in Ann Arbor, Michigan. The chief scientist at SRI International, Dr. Hasan Bahcivan, led his team at SRI to develop the payload while the chief engineer, Dr. James Cutler, led a team of students to develop the satellite bus in the Michigan Exploration Laboratory. There are currently two satellites in the RAX mission.

<span class="mw-page-title-main">SARAL</span> Indian Earth observation satellite

SARAL is a cooperative altimetry technology mission of Indian Space Research Organisation (ISRO) and Centre National d'Études Spatiales (CNES). SARAL performs altimetric measurements designed to study ocean circulation and sea surface elevation.

Technology Education Satellite (TechEdSat) is a successful nano-sat flight series conducted from the NASA Ames Research Center in collaboration with numerous universities. While one of the principal aims has been to introduce young professionals and university students to the practical realm of developing space flight hardware, considerable innovations have been introduced. In addition, this evolving flight platform has tested concepts for Low Earth Orbit (LEO) sample return, as well as planetary nano-sat class mission concepts.

<span class="mw-page-title-main">PhoneSat</span>

PhoneSat is an ongoing NASA project of building nanosatellites using unmodified consumer-grade off-the-shelf smartphones and Arduino platform and launching them into Low Earth Orbit. This project is part of NASA's Small Spacecraft Technology Program and was started in 2009 at NASA Ames Research Center.

<span class="mw-page-title-main">LunIR</span> Spacecraft

LunIR is a nanosatellite spacecraft launched to the Moon collecting surface spectroscopy and thermography. It was launched as a secondary payload on the Artemis 1 mission on 16 November 2022.

<span class="mw-page-title-main">CubeSat for Solar Particles</span> Nanosatellite

CubeSat for Solar Particles (CuSP) was a low-cost 6U CubeSat to orbit the Sun to study the dynamic particles and magnetic fields. The principal investigator for CuSP is Mihir Desai, at the Southwest Research Institute (SwRI) in San Antonio, Texas. It was launched on the maiden flight of the Space Launch System (SLS), as a secondary payload of the Artemis 1 mission on 16 November 2022.

Waves (<i>Juno</i>) Experiment on the Juno spacecraft to study radio and plasma waves

Waves is an experiment on the Juno spacecraft for studying radio and plasma waves. It is part of a collection of various types of instruments and experiments on the spacecraft; Waves is oriented towards understanding fields and particles in the Jupiter's magnetosphere. Waves is on board the uncrewed Juno spacecraft, which was launched in 2011 and arrived at Jupiter in the summer of 2016. The major focus of study for Waves is Jupiter's magnetosphere, which if could be seen from Earth would be about twice the size of a full moon. The magnetosphere has a tear drop shape, and that tail extends away from the Sun by at least 5 AU. The Waves instrument is designed to help understand the interaction between Jupiter's atmosphere, its magnetic field, its magnetosphere, and to understand Jupiter's auroras. It is designed to detect radio frequencies from 50 Hz up to 40,000,000 Hz (40 MHz), and magnetic fields from 50 Hz to 20,000 Hz (20 kHz). It has two main sensors: a dipole antenna and a magnetic search coil. The dipole antenna has two whip antennas that extend 2.8 meters and are attached to the main body of the spacecraft. This sensor has been compared to a rabbit-ear TV antenna. The search coil is overall a Mu-metal rod 15 cm (6 in) in length with a fine copper wire wound 10,000 times around it. There are also two frequency receivers that each cover certain bands. Data handling is done by two radiation-hardened systems on a chip. The data handling units are located inside the Juno Radiation Vault. Waves is allocated 410 Mbits of data per science orbit.

NASA's Pathfinder Technology Demonstrator (PTD) Project is a series of tech demonstrations of technologies aboard a series of nanosatellites known as CubeSats, providing significant enhancements to the performance of these versatile spacecraft. Each of the five planned PTD missions consist of a 6-unit (6U) CubeSat with expandable solar arrays.

<span class="mw-page-title-main">Simulation-to-Flight 1</span> Microsatellite

Simulation-to-Flight 1 (STF-1) is a microsatellite built by the Katherine Johnson Independent Verification and Validation Facility (IV&V) in Fairmont, West Virginia with the collaboration of the West Virginia Space Grants Consortium and West Virginia University.

<span class="mw-page-title-main">SpaceX CRS-27</span> 2023 American resupply spaceflight to the ISS

SpaceX CRS-27, also known as SpX-27, was a Commercial Resupply Service mission to the International Space Station (ISS) launched on 15 March 2023. The mission was contracted by NASA and was flown by SpaceX using Cargo Dragon C209. This was the seventh flight for SpaceX under NASA's CRS Phase 2.

References

  1. 1 2 3 4 5 6 7 "RAX-2 Satellite details 2011-061D NORAD 37853". N2YO. 24 January 2015. Retrieved 25 January 2015.
  2. "Spacecraft Design". Radio Aurora Explorer. University of Michigan. Archived from the original on 2010-11-28. Retrieved 2013-07-10.
  3. "RAX-Radio Aurora Explorer Mission Science Operations". Rax.sri.com. Archived from the original on 2012-04-25. Retrieved 2012-05-26.
  4. "NASA - Expendable Launch Vehicle Status Report". Nasa.gov. Retrieved 2012-05-26.
  5. "NASA - ELaNa: Educational Launch of Nanosatellites". Nasa.gov. 2011-02-14. Retrieved 2012-05-26.
  6. "RAX 1, 2". Space.skyrocket.de. Retrieved 2012-05-26.
  7. "NASA - ELaNa: Educational Launch of Nanosatellites". NASA . Archived from the original on 2023-06-15.
  8. "Tracking Station | Worldwide launch schedule". Spaceflight Now. Retrieved 2012-05-26.
  9. "Mission Science Operations". Radio Aurora Explorer. SRI International. Archived from the original on 2013-06-19. Retrieved 2013-07-10.
  10. "Mission". Radio Aurora Explorer. University of Michigan. Archived from the original on 2012-06-24. Retrieved 2013-07-10.
  11. "RAX Home". Radio Aurora Explorer. SRI International. Archived from the original on 2013-06-19. Retrieved 2013-07-10.
  12. "Northern Lights: First-Ever Measurement of Auroral Turbulence Using a Nanosatellite Radar Receiver". Science Daily . 2012-03-22. Retrieved 2013-07-10.
  13. "Space Weather Researchers from SRI International and University of Michigan Take First-Ever Measurement of Auroral Turbulence Using a Nanosatellite Radar Receiver" (Press release). SRI International. 2012-03-22. Archived from the original on 2013-07-02. Retrieved 2013-07-10.