UP Aerospace has been flying since 2006, albeit at low flight rates, so I wouldn't call that early operation.
T-Minus Engineeringhttp://www.t-minus.nl/"The T-Minus DART is a system for fast and low-cost probing of the upper atmosphere. A certain part of the atmosphere is hardly investigated until now. At altitudes between 50 and 120 km, the air density is too low for balloons to float, and too high for satellites to maintain their orbit. Sounding rockets can be used to perform in-situ measurements, but these are usually too expensive for simple and frequent missions."
Another one left out: bluShift Aerospace (https://www.blushiftaerospace.com/) has been developing at least three different suborbital rockes according to their website (and an orbital launch vehicle), of which the smallest one is expected to have its maiden flight this month.
Liftoff of Stardust 1.0!Top-down view from the launch tower.
I've left out another one. The Dutch/New Zealand: Dawn Aerospace mk.II Aurora (and mk.III) rocketplane(s)The mk.II Aurora can launch a 3U payload to >100km for 150s micro gravity, probing of the atmosphere or hypersonic flight. https://www.youtube.com/watch?v=zo1p9gK_X94
IAF Member @SpaceForest2 Hybrid Rocket Engine SF1000 test No. 4 had many improvements like mass reduction of the combustion chamber, modified injector geometry, stabilization of engine working parameters and more. check out onhttps://youtube.com/watch?v=fnWAetWE6jE&t#IAFMembers
Furthermore, the Safran-Airbus joint venture will present two new products. First, its new Sylex sounding rocket, which has been in development for three years. It will be available in two versions: a single-stage and a more powerful two-stage. These sounding rockets are positioned at the upper end of the spectrum for this type of vehicle, aiming for very high speeds and very high altitudes without actually reaching space. These performance figures remain confidential for the time being.They will launch from a ramp installed at the DGA military facility in Biscarosse (Landes). This type of rocket is necessary to transport scientific experiments to high altitudes to take advantage of microgravity, but also to inject military aircraft such as hypersonic gliders into the upper atmosphere.By developing its own sounding rockets, ArianeGroup is reducing its dependence on American suppliers. The first launch of the VMaX hypersonic glider in 2023, was delayed by a year, mainly due to a delay by the American supplier of the sounding rocket needed to launch the vehicle to high altitude.
To carry out this type of test [tests of a new hypersonic glide vehicle, mentionned to be up to 20,000 km/h or 5.5km/s], the DGA and ArianeGroup rely on sounding rockets manufactured by foreign manufacturers, particularly American ones, which does not allow them to control the deadlines or the sovereignty of the system. Hence the development, currently being finalized, of SyLEX, derived and adapted from the technologies of the M51 (nozzles, thrusters, etc.), in a cheaper and more robust way. SyLEX will ultimately be the transporter of the V-MAX if the latter sees the light of day. It will also be offered to private civilian customers, potentially foreign ones, or to institutions to carry out, for example, experiments in microgravity.
