of Servicing Mission 4, the last servicing mission by the Space Shuttle, NASA installed the Soft Capture Mechanism (SCM), to enable deorbit by either a crewed or robotic mission. The SCM, together with the Relative Navigation System (RNS), mounted on the Shuttle to collect data to "enable NASA to pursue numerous options for the safe de-orbit of Hubble", constitute the Soft Capture and Rendezvous System (SCRS). Possible service missions , the Trump Administration was considering a proposal by the Sierra Nevada Corporation to use a crewed version of its Dream Chaser spacecraft to service Hubble some time in the 2020s both as a continuation of its scientific capabilities and as insurance against any malfunctions in the James Webb Space Telescope. In 2020, John Grunsfeld said that SpaceX Crew Dragon or Orion could perform another repair mission within ten years. While robotic technology is not yet sophisticated enough, he said, with another crewed visit "We could keep Hubble going for another few decades" with new gyros and instruments. In September 2022, NASA and SpaceX signed a Space Act Agreement to investigate the possibility of launching a Crew Dragon mission to service and boost Hubble to a higher orbit, possibly extending its lifespan by another 20 years. Successors There is no direct replacement to Hubble as an ultraviolet and visible light space telescope, because near-term space telescopes do not duplicate Hubble's wavelength coverage (near-ultraviolet to near-infrared wavelengths), instead concentrating on the further infrared bands. These bands are preferred for studying high redshift and low-temperature objects, objects generally older and farther away in the universe. These wavelengths are also difficult or impossible to study from the ground, justifying the expense of a space-based telescope. Large ground-based telescopes can image some of the same wavelengths as Hubble, sometimes challenge HST in terms of resolution by using adaptive optics (AO), have much larger light-gathering power, and can be upgraded more easily, but cannot yet match Hubble's excellent resolution over a wide field of view with the very dark background of space. Plans for a Hubble successor materialized as the Next Generation Space Telescope project, which culminated in plans for the James Webb Space Telescope (JWST), the formal successor of Hubble. Very different from a scaled-up Hubble, it is designed to operate colder and farther away from the Earth at the L2 Lagrangian point, where thermal and optical interference from the Earth and Moon are lessened.