Thursday, June 29, 2006

STS-121 Orbital Elements Released

Image above: In the early dawn of Wednesday morning, STS-121 Pilot Mark Kelly prepares to takeoff in the Shuttle Training Aircraft at Kennedy's Shuttle Landing Facility. The modified Grumman Gulfstream II jet simulates the flight characteristics of an orbiter when practicing landing approaches or other maneuvers. Photo courtesy of NASA/Kim Shiflett.

Courtesy of Gerhard Holtkamp and the SEESAT-L newsgroup. NASA has now posted orbit elements for STS-121 on their Orbital Elements webpage.

Launch is indicated at 1-JUL-2006, 19:48:38 UT.

The first coasting arc is valid from 19:59:06 UT until 20:38:03 UT (1-JUL-06). The state vector given for this arc is in good agreement with the TLEs posted by Ted Molzcan two weeks ago. However the also given (NASA) TLEs for this arc show a discrepancy with the numeric state vector. I get the following TLEs out of the given state vector:

1 0 06182.83270833 0.00000000 00000-0 95600-4 0 1
2 0 51.6328 112.1460 0128427 347.8366 69.9206 16.48997100 1

The ISS entries are listed with the remark that no orbital maneuvers are planned (until at least 9-JUL-2006). However, I found the following remark in the STS 121 press kit about mission objectives:

* Reboost ISS with the orbiter to no more than 186.7 nautical miles average orbital altitude, if propulsive consumables are available. *

I wonder whether we will also see the small unexpected increases that happened during last year's Discovery docking to the ISS. It will be interesting to keep an eye on the ISS orbit over the next two weeks.

Darmstadt, Germany