The
Hubble Origins Probe (
HOP) was a proposal for an orbital
telescope made in 2005 in response to the first cancellation of the fourth
Hubble Space Telescope (HST) servicing mission. It would have used an
Atlas V rocket or similar launch vehicle to launch a much lighter,
unaberrated mirror and optical telescope assembly, using the instruments that had already been built for SM4, along with a new wide-field imager. It would have cost between $700 million and $1 billion.