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Every time a CubeSat gets launched, there is some confusion on what TLEs should be used.   This is the result of the process of launching a new amateur CubeSat with other CubeSats, often several dozen at a time.  We then start the  process of determining which object in a “flock” of CubeSats  is associated with a particular spacecraft.

Pre-launch TLEs that are calculated based on the expected orbit are usually supplied by the launch provider. Pre-launch TLEs are used until post-launch TLEs (for the group of objects that your satellite is in) are released from the US Department of Defense Joint Space Operations Center (JSpOC) based on observations made with cameras and radars.

There is a a 5 to 10 day period of tracking a group of CubeSats until they separate enough to isolate the one of interest. By observing the Doppler shift on transmissions from a particular satellite against the calculated Doppler shift from all candidate object TLEs, we can positively associate an object with a particular satellite. In the case of AMSAT satellites, we then advise JSpOC which object number is “ours”.

Finally, an individual satellite and its associated TLEs are determined and we settle down to an single, accurate, reliable set of TLEs … and all the other “best guesses” go away, although they may be still floating around on the Internet. But, there are so many variables  – did you launch on time, did you get released on time, has the group your CubeSat is in separated enough to identify your satellite, etc. that the process that can be both confusing and annoying at the same time.

AMSAT strives to minimize confusion when distributing TLEs.  Dummy object numbers are used for pre-launch TLEs since final object numbers cannot be assigned yet.    Immediately post launch we may post candidate objects with generic names like “OBJECT C”.    Finally, when positive association between an object number and a spacecraft is made, we will use the common name of the satellite.   We always recommend using TLEs from the Keps mailing list or the current bulletin or bare elements from the AMSAT web site.

by Ray Hoad
WA5QGD
Orbital Elements Manager

At the AMSAT-NA Annual General Meeting in Reno, NV, AMSAT-NA President Joe Spier, K6WAO, announced the next phase of AMSAT’s CubeSat program: GOLF. GOLF, an acronym for “Greater Orbit, Larger Footprint,” is a crucial step towards fulfilling AMSAT’s strategic goals involving high altitude, wide access satellite missions.

As an initial step in the GOLF program, the AMSAT-NA Board of Directors approved the submission of a NASA CubeSat Launch Initiative proposal for the GOLF-T satellite project. The GOLF-T project will serve as a rapidly deployable Low Earth Orbit (LEO) testbed for technologies necessary for a successful CubeSat mission to a wide variety of orbits, including LEO, Medium Earth Orbit (MEO), Geosynchronous Orbit (GEO), Highly Elliptical Orbit (HEO), or beyond.

AMSAT-NA Vice-President Engineering Jerry Buxton, N0JY, said “The GOLF-T project tees off the next phase of our CubeSat program. GOLF-T provides AMSAT hardware and knowledge for Attitude Determination and Control (ADAC) capability and the opportunity to develop a 3U spaceframe with deployable solar panels that can be used in LEO or HEO missions, two of the major systems required in future GOLF and HEO missions.”

In addition, GOLF-T provides the opportunity for rapid deployment and on orbit testing of the AMSAT’s Advanced Satellite Communications and Exploration of New Technology (ASCENT) program’s technology, including radiation tolerant transponder and Integrated Housekeeping Unit (IHU) technologies that will lead the way for low cost commercial off-the-shelf (COTS) systems that can function in the MEO and HEO radiation environments. GOLF-T will also provide for the development of “Five and Dime” Field-Programmable Gate Array Software Defined Radio (FPGA SDR) transponders for use on a variety of missions and orbits.

The launches of AMSAT satellites Fox-1Cliff and Fox-1D have been rebooked from the original Spaceflight Formosat-5/Sherpa mission aboard a SpaceX Falcon 9  on to two separate new launches.

Fox-1D will now ride to orbit on an Indian PSLV vehicle scheduled to launch from Satish Dhawan Space Centre in Sriharikota, India in late 2017.

Fox-1Cliff will launch on Spaceflight’s SSO-A dedicated rideshare mission aboard a SpaceX Falcon 9 scheduled to launch from Vandenberg Air Force Base in California in late 2017 or early 2018.

These moves will serve to expedite the launch of these two satellites, both of which carry an amateur radio U/v FM repeater and an experimental L/v FM repeater.  The satellites also carry scientific experiments, from university partners Penn State, Vanderbilt University ISDE, Virginia Tech, and University of Iowa.

In addition to the launch of Fox-1Cliff and Fox-1D, AMSAT is awaiting the launches of RadFxSat and RadFxSat-2. RadFxSat is currently manifested for launch on August 29, 2017 aboard the ELaNa XIV mission, as a secondary payload with the Joint Polar Satellite System (JPSS)-1 on a Delta II from Vandenberg Air Force Base, California. RadFxSat-2 will be launched by Virgin Galactic on their LauncherOne air launch system from Mojave, CA on the ELaNa XX mission no earlier than December 2017.