When Rockets End Production

An unexpected threat to a European Space Agency (ESA) mission called Biomass has appeared as they're closing in on a launch date according to the European Spaceflight newsletter and linked to by Ars Technica.

Two of the four tanks necessary to power the fourth stage of the final Vega flight disappeared several months ago, leaving Avio scrambling to find an alternate solution.

The Vega is kind of an odd duck among modern rockets.  Built by the Italian-based company Avio, Vega is a smallish booster, capable of little more than 2 metric tons to low-Earth orbit on a solid-fueled first stage.  The propellant tanks from the upper stage, powered by dimethylhydrazine and nitrogen tetroxide fuel—went missing earlier this year.

Now, it seems that the propellant tanks have been found. However, the newsletter says, the tanks were recovered in a dismal state, crushed, alongside metal scraps in a landfill. Someone, apparently, had trashed the tanks. This is a rather big problem for Avio, as this was to be the final Vega rocket launched, and the production lines are now closed for this hardware.

This puts the Biomass mission and the ESA in a bit of deep water.  The EU has no other launch vehicles available.  Because of the issues with Vega C (example here) and the Ariane 6 being well behind in its development (despite the recent successful test), there's no way for the 1,250-kg Biomass satellite to get to orbit.  It's too heavy for Rocket Lab's Electron and the other smaller lift vehicles, but the trend is definitely against the Vega - probably part of the reasons this is set to be the final mission for the rocket. 

Vega has two big problems; the first is cost.

While the vehicle's marketer, Arianespace, does not publicly publish prices, a Vega launch costs approximately $35 million to $40 million. This was barely competitive a decade ago when the vehicle debuted. Now it's out-of-bounds with a new generation of small launch companies that offer lower prices, or the more reliable Falcon 9, which only costs about 50 percent more for much more lift capacity.

The second is reliability.  The Vega rocket has suffered two failures in its last seven launches, giving it a lifetime failure rate of 10 percent across 21 launches.

There are two options currently being discussed.  

So what will Avio do? According to European Spaceflight, officials are working on two options. The first involves using old propellant tanks that were built for qualification tests of the Avio rocket more than a decade ago. There are four such tanks, and the company could subject two of them to re-qualification tests and, if those tests go well, employ the other two tanks for the launch. Understandably, engineers have some concerns about the integrity of these tanks, which in addition to their age were never meant to fly.

Another option is to modify the upper stage that is used by the Vega C rocket. While there are some commonalities between the Vega and Vega C upper stages, there are differences, and the new AVUM+ upper stage was not intended to fly on the original Vega rocket. It remains to be seen whether the European Space Agency is willing to support the launch of its valuable satellite on such a kludged-together rocket.

Image credit: ESA–S. Corvaja, 2013

The fact that the old tanks "were never meant to fly" should not be a concern.  It's an invalid qualification test if what you're testing isn't identical to flight hardware.  

The Biomass mission, by the way, is a synthetic aperture, P-band radar intended to monitor forests around the earth to assess their health and if/how their health is changing.  If you'll pardon the expression, I've been around some radar systems in my day, and I've never heard of a P-band radar, or really a P-band anything.  One source I found said it's close to 70cm, which many hams will recognize as nearly 430 MHz (428.6 MHz), while another says 225-390 MHz.  The mission's Synthetic Aperture antenna is 12m in diameter, which sounds like it will produce a pretty narrow beam.  I can't imagine them not steering the antenna.