Post Tue Jul 19, 2011 9:46 am

The scientific program of NASA suffers another loss

Friday, 4th of February, the scientific program of NASA suffered an important loss as the Glory satellite failed to reach an operational orbit.
NASA did not handle directly the Glory mission but it had subcontracted it to Orbital Sciences Corporation- for the designing and building of the spacecraft, while the launch was coordinated by Orbital Launch System Group.
The entire program costs the American agency 424 millions dollars with a part of 54 millions for the launch.

This is not the first incident of this kind, but the second one involving the Orbital company, after the one from 24th of February 2009 when NASA lost the 273 millions dollars OCO (Orbiting Carbon Observatory) satellite due to a launcher failure. The same rocket failed also in the past, to be more precise in 2001, when other 4 satellites were completely destroyed: OrbView4, QuickTOMS, SBD and Celestis05.
Statistically this does not look very good- from 8 performed flights 3 were failures.
The rocket used now is the same configuration as in the past – a Taurus XL- and the failure is apparently caused by the system which is responsible for the separation of the fairing capsule by the rocket’s final stage. As the separation has not occurred, the orbital injection was impossible, all the onboard satellites falling down to the Pacific Ocean.
After the 2009’s incident, as a contra-measure, Orbital changed completely the solution used for this separation system, borrowing the one from the Minotaur 4 rockets. It appears however that without much success, as the new solution, despite the intensive ground tests performed, was not better and dramatically affected the company’s image.

Taurus XL is the ground launched version of the air missile Pegasus, sharing the same 3 stages configuration (powered by Orion 50SXLG, Orion 50XL and respectively Orion 38 engines) all helped by a supplementary stage used for take off (powered by a Castor 120 engine). All these engines use solid fuel. The rocket made its debut in 1994 and has counted, as we said before, 5 successful launches with 10 satellites placed into orbit.
Weighting 73 tons and having a height of 28 meters, the rocket is able to carry in a LEO orbit, payloads up to 1300 kg.

We should also provide some details about the Glory satellite. This is a medium size 1.9 x 1.4 m satellite, weighting 545 kg and being built on an Aluminum octagonal structure.
As part of the “Earth observation” program, it should provide from a LEO 705 km altitude SSO orbit, scientific data for the study of the atmosphere and climate changes.
Orbital has built the satellite on a LEOStar platform taken from another program which was cancelled in 2000- the VCL (Vegetation Canopy Lidar) satellite.
The electrical system of the satellite is served by 3 solar panels (2 external and another one mounted on the satellite’s structure) and is able to offer up to 766 W, more than enough for the onboard consumption estimated as 400 W (150 W used for the scientific instruments).
The AOCS (Attitude and orbit control system) ensures a three-axis stabilization of the spacecraft making use of a monopropellant propulsion system (with a reserve of 45 kg of fuel) composed of 4 thrusters, 4N each.
For at least 3 years (the guaranteed lifetime) and going up to 5 years (what the designers expects) the satellite should work as part of the A-train NASA’s constellation together with Aqua, CloudSat, Calipso and Aura.

The Glory satellite carries 3 scientific experiments: APS (Aerosol Polarimetry Sensor), CCS (Cloud Camera Sensor) and TIM (Total Irradiance Monitor) inherited from the SORCE (Solar Radiation and Climate Experiment) satellite.
APS, built by Raytheon Inc. from El Segundo, California, is a sensor able to produce observations about aerosols and clouds, observations used by the scientific community to determine the global distribution of natural or industry created aerosols, their impact to the radiation’s level and their effect for the climate change.
CCS, built by Ball Aerospace and Technologies Corporation (BATC) from Boulder, Colorado, is a high resolution radiometer which calculates the distribution of the clouds in atmosphere. The measurements are used together with the ones coming from the APS.
TIM, built by University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, Colorado, is a radiometer which counts the solar radiation. It is mounted on a platform which can move independently from the spacecraft movement and by this ensuring a permanent pointing of the instrument to the Sun. Therefore in the illuminated halve of the orbit it will measure the solar energy and latter on these measurements will be used to establish a daily average.

Going back to the launch itself, this took place at 10:09 GMT from the complex 576E of the Vandenberg space centre in California. It came almost 2 weeks from the initial launch date (23rd of February 2011) which was cancelled because of some ground equipment problems. The flight, at least in theory, was a short one, only 15 minutes.
The first stage should carry the entire ensemble for approximately 85 seconds. Then the second stage is powered on for another 85 seconds, followed by the third stage for 79 seconds. At moment T0+02:58 the fairing should be jettisoned and at T0+04:11 the third stage should stop functioning leaving the ensemble in an intermediate transfer orbit.
At T0+09:58 the fourth stage should activate in order to increase the perigee’s height and to circularize the orbit, and latter on at T0+11:10 the Orion 38 engine should separate from the rocket.
Immediately should follow the orbital injection of the principal payload (the Glory satellite) and at T0+13:05 the separation of the adjacent payload (3 small Cubesats).
Unfortunately, the plans have been ruined dramatically when the flight engineers have seen the failure of jettisoning followed in a short time by the atmospheric re-entry.

Which is the auxiliary payload which accompanied the Glory satellite? They are 3 experimental platforms called: E1P, Hermes and KySat1.
E1P or Explorer 1 Prime is a Cubesat nanosatellite built by SSEL- Space Science and Engineering Laboratory of Montana State University celebrating the 50 years from the Explorer 1 mission (which discovered the electrons captured by the Earth’s magnetic field).
Hermes is another Cubesat, this time built by Colorado University, while KySat1 is a Cubesat built in Kentucky.

After this incident, the Taurus XL rocket is not planned to be back into operation too soon- the next launch is programmed at this moment somewhere in 2013 when it should go to orbit with a replacement for the OCO satellite lost in 2009.
Orbital will have however another launch in Mai, when its Minotaur 1 rocket will carry the ORS-1 satellite.