Editing Project Vanguard (section)

== Launch history ==
Test vehicle launches
The first Vanguard flight, a successful [[suborbital]] test of the [[Vanguard TV0]] single-stage vehicle, was launched on 8 December 1956. On 1 May 1957, the two-stage test vehicle TV1 was successfully launched. Vanguard TV2, another successful suborbital test, was launched 23 October 1957.

The Vanguard rocket launched three satellites out of eleven launch attempts:
# [[Vanguard TV3]] – 6 December 1957 – Failed to orbit {{cvt|1.36|kg}} satellite – low tank pressure caused engine cutoff T+2 seconds<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGT3 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# [[Vanguard TV3BU|Vanguard TV3 Backup]] – 5 February 1958 – Failed to orbit {{cvt|1.36|kg|lb|abbr=on}} satellite – control failure caused vehicle breakup T+55 seconds<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGT3B |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# ''[[Vanguard 1]] – 17 March 1958 – Orbited {{cvt|1.47|kg}} satellite''<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1958-002B |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# [[Vanguard TV5]] – 28 April 1958 – Failed to orbit {{cvt|9.98|kg}} satellite – 3rd stage separation failure<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGT5 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# [[Vanguard SLV-1]] – 27 May 1958 – Failed to orbit 9.98&nbsp;kg satellite – 2nd stage attitude control failure prevented the 3rd stage from entering the correct angle for orbital insertion<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGSL1 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# Vanguard SLV 2 – 26 June 1958 – Failed to orbit 9.98&nbsp;kg satellite – 2nd stage lost thrust after only 8 seconds of burning due to fuel line obstruction<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGSL2 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# Vanguard SLV 3 – 28 September 1958 – Failed to orbit 9.98&nbsp;kg satellite – 2nd stage insufficient thrust for orbital insertion due to fuel line obstruction<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGSL3 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# ''[[Vanguard 2]] – 17 February 1959 – Orbited {{cvt|10.8|kg}} satellite''<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1959-001A |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# Vanguard SLV 5 – 13 April 1959 – Failed to orbit {{cvt|10.3|kg}} satellite – 2nd stage hydraulics failure led to loss of control<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGSL5 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# Vanguard SLV 6 – 22 June 1959 – Failed to orbit 10.3&nbsp;kg satellite – 2nd stage exploded due to stuck helium vent valve<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=VAGSL6 |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>
# ''[[Vanguard 3]] –18 September 1959 – Orbited {{cvt|22.7|kg}} satellite''<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1959-007A |access-date=2023-11-30 |website=nssdc.gsfc.nasa.gov}}</ref>