MMS launch; Payload separation, CCAM and fueldump visible from North America

From: C. Bassa via Seesat-l <>
Date: Tue, 10 Mar 2015 17:02:10 +0100
An Atlas 5 rocket will launch MMS, the Magnetospheric Multi-Scale
mission on March 13th, between 02:44 and 03:14UT, from CCAFS. The
mission overview booklet shows that the Centaur upper stage will
insert the payload into a 585x70169 km orbit inclined at 28.77
degrees, after the stack has coasted in a LEO orbit to the first
ascending node.

Based on the time, latitude and longitude of the MECO-2 and MMS-1
separation events, I use the known perigee, apogee and inclination to
fit the RA of the ascending node, argument of perigee and mean
anomaly. The fit yield the following orbital elements, which are valid
from MECO-2 to the MMS-1 separation:

MMS GTO Coast (02:44UT launch)
1 84001U 15999A   15072.11388889  .00000000  00000-0  00000-0 0    00
2 84001  28.7700  29.0124 8332309  25.8172 339.9766  1.01758185    09
MMS GTO Coast (03:14UT launch)
1 84002U 15999A   15072.13472222  .00000000  00000-0  00000-0 0    08
2 84002  28.7700  36.5268 8332309  25.9621 340.0397  1.01758185    05

These elements span the start and end of the launch window.

The payload consists of four identical spacecraft (MMS-1 to 4), which
will be released in 5 minute intervals after insertion into the GTO
type orbit. The following table gives the UTC timings from the mission
overview, and the shadow entry and exit as per the elements.

Event            84001     84002
Launch        02:44:00  03:14:00
MECO-2        04:02:11  04:32:11
MMS-4 sep     04:16:11  04:46:11
MMS-3 sep     04:21:11  04:51:11
MMS-2 sep     04:26:11  04:56:11
MMS-1 sep     04:31:11  05:01:11
Shadow entry  04:36:14  04:57:11
Shadow exit   05:17:14  05:31:31

As of yet there are no broadcast warnings that suggest that the
Centaur upper stage will be deorbited. This may mean it will be
inserted into Solar orbit. For either possibility, it is expected that
the Centaur will perform a Contamination and Collision Avoidance
Maneuver (CCAM), followed by the dumping of the remaining fuel.

The ground track from the mission overview shows that the separation
of the payloads and the subsequent CCAM and fueldump should be visible
from North America. Note though that the payloads and upper stage will
enter the shadow around the times specified in the above table.

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Received on Tue Mar 10 2015 - 11:05:40 UTC

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