Happy Satellite Collision Day! It is 10 years since Russia and Iridium got too close for comfort • The Register
As Elon Musk crowed over the performance of SpaceX’s Raptor engine and Northrop Grumman’s Cygnus departed the International Space Station (ISS), debris watchers were ruing the 10th anniversary of the first accidental hypervelocity satellite collision.
On 10 February 2009, a 950kg Russian military satellite smacked into an Iridium Comms bird, destroying both spacecraft and leaving a cloud of debris large enough to give Sandra Bullock the jitters.
The Russian sat, originally launched in 1993, was out of service and had no propulsion system. Iridium 33, on the other hand, was doing fine until that day. The two were expected to pass as close as 584m to each other but ended up colliding, demonstrating the need for better tracking data and generating a cloud of more than 2,000 pieces of debris, some of which has required the ISS to make the odd avoidance manoeuvre.
The debris has since begun to re-enter Earth’s atmosphere, but the incident remains a salutary reminder that orbital space is getting a bit crowded. It is also justification for regulations requiring that satellites be able to either send themselves into a graveyard orbit at the end of their mission or retain enough manoeuvrability to send themselves to a fiery death hurtling towards terra firma.
Nobody needs a real-life sequel to the Clooney and Bullock vehicle Gravity.
Flight controllers in Houston worked with @northropgrumman and astronauts aboard the International @Space_Station to release the Cygnus cargo resupply craft at 10:16 am CT today. Cygnus departed with over 5,500 lbs of trash after an 81-day stay on the station’s Unity module. pic.twitter.com/hAAk3XB3z3
— Johnson Space Center (@NASA_Johnson) February 8, 2019
Also headed back to Earth is Northrop Grumman’s Cygnus cargo freighter after 81 days spent attached to the ISS.
The spacecraft – numbered NG-10 and named the “SS John Young” in honour of the moonwalker who died last year – was loaded with over 2.5 tonnes of trash from the space station to be disposed of when the thing eventually burns up in the atmosphere.
Unlike SpaceX’s Dragon, the Cygnus doesn’t enjoy a soft landing, and certainly not in one piece.
The Cygnus has, however, been pressed into duty after its 8 February departure from the ISS. The spacecraft will spend a little longer puttering around in orbit, deploying nano satellites and testing a communications system before it’s killed.
Already deployed some 62 miles above the ISS’s orbit are two cubesats, launched from a deployment mechanism called SlingShot, which arrived at the ISS on SpaceX’s CRS-16 mission and was installed in the Cygnus by the crew of the orbital outpost.
The hardworking spacecraft is also due to deploy two more satellites for NanoRacks, on 13 February, in the form of the United Arab Emirates’ MySat-1 and the US Naval Research Laboratory’s CHEFSat, which is not a reference to firing Gordon Ramsay into orbit but instead the Cost-effective High E-Frequency Satellite.
The final task for the Cygnus will be to deploy KickSat-2, a CubeSat that will in turn deploy 100 tiny ChipSats, which integrate power, computing and sensing equipment on a 3.5cm2 circuit board.
The Cygnus will eventually be disposed of on 25 February.
Musk feels the pressure
Back on Earth, Elon Musk continued extolling the virtues of SpaceX’s Raptor engine, claiming the power plant had now reached 268.9 bar of chamber pressure, greater than that of the venerable Russian RD-180 engine used to power United Launch Alliance’s Atlas V.
— Elon Musk (@elonmusk) February 11, 2019
While ULA is looking to Jeff Bezos and his Blue Origin rocketeers to replace the RD-180 (which has become problematic to use in light of ongoing political shenanigans), SpaceX’s Raptor remains destined for the next generation of Musk’s rockets. ®