Today we have been reflecting on an impactful experience that happened on this day in 2008! After a failure of its Briz-M upper stage shortly after launch on March 14, 2008, the AMC-14 communications satellite was left stranded in an inclined geostationary transfer orbit. John Carrico, Owner, CTO at SEE and Mike Loucks, CEO at SEE developed a recovery trajectory to deliver the spacecraft to its originally intended orbit. Changing the angle between a spacecraft’s orbit plane and the equator is expensive in terms of propellant. Since AMC-14 was stranded near an inclination of 52 deg, propellant could be conserved by boosting the apogee of the spacecraft’s orbit out to lunar distance. Two lunar encounters (a “double lunar swingby”) reduced the inclination to 0 deg (an equatorial orbit) and raised perigee to GEO altitude. Perhaps counterintuitively, the propellant required for these large changes in altitude was less than that required to reduce inclination propulsively. Ultimately, AMC-14 did not utilize a double-lunar swingby trajectory to reach GEO. Instead, a series of low-thrust maneuvers were performed to raise orbit and eventually reach an inclined, geosynchronous orbit. The SEE team has studied the use of double lunar swingby trajectories for other applications, including transferring a satellite from a lunar rideshare to GEO. Stephen West presented this work at last year’s Spaceflight Mechanics Meeting. *link to paper: https://lnkd.in/gA2gbH42 Double lunar swingbys are one of the “tools” in the astrogator’s toolbox. For resource constrained missions, lunar gravity assists can enable large orbit changes while conserving propellant. Every day, the SEE team applies techniques like this to solve challenging mission design problems!
📡🚀🌒Sam Peterson
8mo
The team at Space Exploration Engineering are magicians in orbital dynamics.
Jack Showalter
9mo
No idea what most of this means, so even more impressed!
Brett Bonine
9mo
That’s brilliant
Space Consultant
9moHGS1 was the first and only spacecraft to use a double lunar flyby to achieve a geosynchronous orbit in 1998. AMC-14 had a near identical failure 10 years later, but with better initial orbital parameters for a double lunar flyby to achieve GEO. SES, the owner of the LMC spacecraft, contacted me 2 days later to direct a team with SEE expertise to design the mission. Hughes/Boeing received a patent for this technique in 2000. Unfortunately, SES had a lawsuit with Boeing over replacement cost for another spacecraft lost during launch, which led to SES termination of rescue efforts 2 weeks later. A second attempt to use the double lunar flyby sponsored by Protostar (similar to HGS successful efforts to get a deal with the Asiasat 3 insurers) failed a month later. SEE(Mike) was a key member of the team. A third attempt to propose a degrading double lunar flyby, or super-synchronous transfer orbit for a lower inclined geosynchronous orbit, to the government (Space Command, the new owner) never occurred, because they immediately started raising perigee, using propellant required for GEO or lower inclined GSO. The HGS1 story is described in my recent Linked-In post, "Marquis Life Achievement Award to Jeremiah O Salvatore". 👴