Hubble Origins Probe

{{Short description|Proposed orbital telescope}}

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.{{cite press release

| title = Hubble Option

| publisher = Johns Hopkins University Applied Physics Laboratory

| date = 2005

| url= http://solarsystem.nasa.gov/news/display.cfm?News_ID=10380

| archive-url= https://web.archive.org/web/20050306054049/http://solarsystem.nasa.gov/news/display.cfm?News_ID=10380

| url-status= dead

| archive-date= 2005-03-06

| access-date = 30 June 2013 }} 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.{{cite journal | title = ASTRONOMY: Hearing Highlights Dispute over Hubble's Future

| journal = Science

| volume = 307

| issue = 5711

| pages = 831

| date = 2005

| doi = 10.1126/science.307.5711.831| author = Lawler, A. | pmid = 15705817 | s2cid = 152395132

}}

Funding for the mission was never allocated; in February 2005, Sean O'Keefe, the NASA administrator who had cancelled SM4, resigned. Michael D. Griffin, NASA administrator after O'Keefe, reinstated the servicing missions,{{cite web

| last = Harwood

| first = William

| title = 'Go' for Hubble servicing mission

| publisher = CBS NEWS Space Place

| date = 31 October 2006

| url = http://www.spaceflightnow.com/shuttle/sts125/061031approval/

| access-date = 1 July 2013

}} making HOP redundant.