RCO – Saving a crippled Discovery
The first ever Shuttle mission to fly with an official rating of “unacceptable risk”, STS-121 will debut a concept that will allow Discovery to land herself in an STS-300 “Safe Haven” scenario.
The Autonomous Orbiter Rapid Prototype (AORP) is a modification that matured to full RCO (Remote Control Orbiter) – which allows the orbiter to complete the final landing procedures that currently require human intervention.
The concept, which was completed as far back as 2004 – possibly as part of NASA’s post Columbia (STS-107) review process – is officially classed ‘…to develop a design for a system to enable autonomous landing of the Orbiter in the event a ‘Safe Haven’ of the crew was declared.’ It is also known as the Remote Controlled Orbiter IFM cable.
To record, the only orbiter that has completed an unmanned landing came during the one and only flight of the Soviet Shuttle orbiter Buran, although her flight – which was fully unmanned from launch to landing – employed a very complex style of remote control, unlike the AORP.
The NASA system is a simple ‘box of tricks’ that will take over the human interaction with Discovery’s GPC (General Purpose Computers) via electrical cables plugged her into the flight deck panels, allowing for Air Data Probe Deploy, Landing Gear Deploy, and deployment of the Drag Chute to be commanded via the AORP.
The AORP would be used in a scenario where an orbiter has suffered damage on ascent. Once the undesirable call has been made by Shuttle managers on the ground, Discovery’s crew would take up the ‘safe haven’ of the International Space Station (ISS).
While Atlantis would be prepared for her LON (Launch On Need) rescue mission, known as STS-300, to bring the crew home from the ISS, Discovery would have the box installed, before being commanded to undock from the station, to make way for the subsequent arrival of her sister.
Previous plans involved the damaged orbiter to de-orbit into a watery grave in the Pacific Ocean, but now she’ll have a fighting chance to return home in one piece, without risking the lives of her crew.
This is not only a desirable option to save a couple of billion dollars worth of tax payers money being sent to the bottom of the ocean, it is also a welcomed option for those that work with – and care for – the orbiters, many of whom openly class their beloved orbiters as part of the NASA family.
Due to an STS-300 scenario deeming Discovery to be at risk of disintegrating on re-entry, Flight Directors will likely have the option of waving off the return of Discovery – almost certainly to Edwards Air Force base in California — if she had controllability issues during re-entry. That would lead to a ditching in the ocean.
The role of the Flight Directors at the Johnson Space Center in such an unmanned re-entry and landing will be crucial, as they help guide the orbiter back home in a never previously attempted scenario.
Should she make it home, AORP would not only allow for Discovery to be saved, but the data gained from her risky return would prove to be invaluable for any future assessment on a damaged orbiter’s ability to survive – where Columbia failed during her ill-fated re-entry in 2003.
While this extra capability is simple – and more so an obvious step for Shuttle managers to take – NASA has been very tight lipped on making the media and public aware of AORP’s existence.
Back in February, NASASpaceflight.com asked NASA PAO’s Kyle Herring about this modification’s status, to which he commented: ‘The capability currently does not exist for the shuttle to return to earth uncrewed, but there is some engineering work ongoing that potentially might provide the technical capability at some time in the future.’
However, upon learning of the AORP Project was completed October 2004, both the United Space Alliance PAO Tracy Yates and the modification’s named contact, Johnson Space Center’s Michael T Garske, said they were unable to comment – and recommended inquiring to NASA PAO. A request for information, sent five days ago (to NASA PAO) prior to this publication, has not received a response.
While NASA may be wary of the media twisting this modification as a potential concern NASA has over the remaining flights of the Shuttle, the extra capability of the orbiters through AORP should be seen as encouraging.
AORP could also prove useful during emergency scenarios – such as an incapacitated crew on the flight deck – during the final stages of landing, in which an orbiter has only one chance to complete its landing.
Noting back to Buran’s unmanned landing, lessons can be learned by saving an orbiter from a simple ditching. Buran herself managed to make it back to the Baikonur Cosmodrome in Kahazstan, even after serious in-flight damage.
So serious was the damage, it was unlikely she would have flown again – especially given the cost of the repair work. Buran, sadly, was later destroyed when her hanger roof collapsed on top of her, due to the weight of heavy snow.
**Resource: Buran Historical Pages**