Could OneWeb's satellites be launched on Electron rockets?

Question

OneWeb's satellites weigh about 150 kg each, which is within the range of the Electron rocket. However I am not sure about the target orbit(s).

Technically speaking, could OneWeb launch its satellite constellation on Electrons?

Answer 1

tl;dr: According to currently published numbers, No, not at present, but...

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The Wikipedia article section OneWeb satellite constellation; Design characteristics tells us:

The satellites in the OneWeb constellation are approximately 150 kg in mass, a bit smaller than the 2015 design estimate of 175–200 kg (386–441 lb). The 648 operational satellites are to operate in 18 polar orbit planes at 1,200 kilometres (750 mi) altitude.

The total number of satellites has been steadily decreasing from higher values, the excellent presentation A Technical Comparison of Three Low Earth Orbit Satellite Constellation Systems to Provide Global Broadband dated October 2018 for the 69th International Astronautical Congress 2018, Bremen, Germany still lists 720 satellites.

The constellation is strictly polar orbits, the slide below shows an inclination of 86.4 degrees which should be accessible by launches both from New Zealand and Scotland.

• Why is Rocket Lab's New Zealand launch site good for polar orbits?
• Is there a significant difference between launching a polar orbit mission south from New Zealand versus launching it north?
• Why put both Orbex and Rocket Labs on adjacent launch pads in Scotland? (currently unanswered)

Both Wikipedia and Rocketlab say that the vehicle can lift 150 kg to a nominal 500 km sun-synchronous orbit. That's an inclination of about 97 degrees, very slightly retrograde. OneWeb's orbits are very slightly prograde.

The question is if that difference can get us from 500 km to 1200 km.

The latitude of Mahia Peninsula is 39 degrees south. Earth's rotation speed there is 361 m/s but very little of it is used launching in the polar direction. Nonetheless $361 \text{m/s} \times \cos(97°)$ is -44 m/s while $361 \text{m/s} \times \cos(86.4°)$ is +23 m/s. This is scratching the bottom of the barrel, but the orbital speed difference between a 500 km and 1200 km Earth orbit is 7600 - 7250 or 350 m/s, much bigger than that little bit of boost could compensate.

Answer: According to currently published numbers, No, not at present, but... They can put 150 kg into a polar orbit at 500 km, but not 1200 km. The difference is 350 m/s and that's a bit hard to make up.

This doesn't rule out incremental improvements on the Electron, we certainly saw a steady march of incremental improvements on the Falcon 9 from 1.0, to 1.1 to FT and the Electron is in its early days.

How long would it take?

Wikipedia's Rocket Lab Launch Complex_1; Decision for Mahia says:

The Mahia site is licensed for a maximum launch rate of once every 72 hours over a period of 30 years—Rocket Lab believes the actual rate would average once per week—while the Kaitorete site would only have been licensed to launch once per month.

To launch 648 satellites at a rate of once every 72 hours would take five years, and that is probably a little too slow for their business model. But combine that with launches from Scotland and it seems possible.